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University of Groningen
Sustainable employability of ageing workersKoolhaas, Wendy
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Sustainable employability of ageing workers
The development of an intervention
Wendy Koolhaas
Colofon
This study was conducted within the Research Institute SHARE of the Graduate School of
Medical Sciences, University Medical Center Groningen, University of Groningen and
under auspices of the research program Public Health Research (PHR).
The printing of this thesis was financially supported by the Graduate School of Medical
Sciences, Research Institute SHARE, University Medical Center Groningen, and the
University of Groningen.
Title Sustainable employability of ageing workers. The development of an
intervention. – with summary in Dutch
Cover design Bert Cornelius en Wendy Koolhaas
Foto Monique van den Berg; wandelaar Robbert de Bruin
Printed by Gildeprint, Enschede
ISBN 978‐90‐367‐6722‐4
© 2014 Wendy Koolhaas, The Netherlands
All rights reserved. No part of this thesis may be reproduced or transmitted, in any form or
by any means, without permission of the author.
Sustainable employability of ageing workers
The development of an intervention
Proefschrift
ter verkrijging van de graad van doctor aan de Rijksuniversiteit Groningen
op gezag van de rector magnificus, prof. dr. E. Sterken
en volgens besluit van het College voor Promoties.
De openbare verdediging zal plaatsvinden op woensdag 22 januari 2014 om 11.00 uur
door
Wendy Koolhaas geboren op 5 januari 1980 in de Noordoostpolder
Promotores Prof. dr. J.J.L. van der Klink Prof. dr. J.W. Groothoff Copromotor Dr. S. Brouwer Beoordelingscommissie Prof. dr. ir. A. Burdorf Prof. dr. F.J.H. van Dijk Prof. dr. M.F. Reneman
Paranimfen: Cindy Koolhaas Rudy Koolhaas
Contents
Chapter 1 General introduction
9
Chapter 2 In‐depth study of the workers’ perspectives to enhance sustainable working life: comparison between workers with and without a chronic health condition J Occup Rehabil. 2013;23(2):170‐9
19
Chapter 3 Toward a sustainable healthy working life: associations between chronological age, functional age and work outcomes Eur J Public Health. 2012;22(3):424‐9.
43
Chapter 4 Chronic health conditions and work ability in the ageing workforce: the impact of work conditions, psychosocial factors and perceived health. Int Arch Occup Environ Health. 2013 May 16. [Epub ahead of print]
61
Chapter 5 Coping, job control and social support as adaptation determinants of work ability among ageing workers with and without a chronic health condition. Submitted for publication
85
Chapter 6 Enhancing a sustainable healthy working life: design of a clustered randomized controlled trial. BMC Public Health, 2010; 10; 461
105
Chapter 7 Effectiveness of a problem‐solving based intervention to improve sustainable employability of ageing workers. Submitted for publication
127
Chapter 8 General discussion
153
Summary Samenvatting Research Institute for Health and Research (SHARE) and previous dissertations Dankwoord Curriculum vitae
171 179 189 195 201
Voor Eddy en Kim Eelde, december 2013
1
General introduction
General introduction
11
AGEING OF A WORKING POPULATION
The ageing population is an important topic in political, societal and economic debates,
especially regarding the working population1‐3. Ageing is not simply an effect of time, but
refers to changes in biological, psychosocial and social functioning over time, and
therefore has an effect on a personal, organizational and societal level4‐8. To offset some
of the pressure that an ageing population will place on the economy, it is important to
increase the labour market participation of older workers9.
In the Netherlands, as in most welfare states, the impact of an ageing population is being
felt and is changing the face of the country10. The relative demographic decline has been
driven by a sharp fall in fertility rates and increased life expectancy3,11. The average
fertility rate declined from 2.5 in 1970 to 1.6 in 1980 and was stable for the last decades
around 1.7 children per female (Central Bureau of Statistics 2013). In addition, life
expectancy has increased from 72.5 years for males and 79.2 years for females in 1980 to
79.1 and 82.8 years, respectively, in 2012, and is expected to rise above 85 years by 2050
(Central Bureau of Statistics 2013)12. Moreover, the life expectancy of older people has
increased particularly rapidly. While men and woman who are currently 65 can now
expect to live for another 17.9 and 20.8 years respectively, this is forecast to increase to
20.7 and 23.5 years respectively by 2050 (Central Bureau of Statistics 2013). This means
that employers no longer have access to a steady supply of young, educated workers and
will need to rely more than before on older workers to remain competitive in the global
marketplace in the future.
Since 2006, the Netherlands has successively introduced a number of financial
instruments to encourage older workers to continue working and employers to hire them
and retain them in employment13. For example, an important aspect is increasing the
retirement age determined by the public pension system from 65 to 67 years of age; the
statutory retirement age will rise by one month per year from 2013 onwards till in 2025
the pension age is set at 67. The factual age at which people retire have risen from 61.0
years of age on average in 2000 to 63.6 years in 2012. Moreover, while 30% of workers
who retired in 2011 were 65 or older, this percentage increased to 42% in 2012 (Central
Bureau of Statistics 2013). By 2025, the retirement age will have increased to 67 and
might rise further as life expectancy increases13.
While until recently an early exit from the labour market was supported in the cases of
workers with age‐related problems such as a chronic health condition or a physically
demanding job, such workers now have to continue working despite their vulnerability in
Chapter 1
12
the labour market and their weakened capacity. From literature it is known that especially
after the age of 45, a variety of factors can diminish a worker’s quality of life, such as an
age‐related decline in health which can negatively affect various cognitive processes (i.e.
memory recall, speed and sensory functions) and musculoskeletal capacity (i.e. poorer
muscular strength, endurance and flexibility)14‐17. The ageing process is also associated
with increased absences due to sickness18 and the discontinuation of working life19‐21. To
enable workers to continue work participation and increase their sustainable
employability, it is important to maintain and promote their health and vitality.
Knowledge about the determinants as well as the perspectives of ageing workers
concerning continuing work until retirement age is required; at the one hand to
understand how they might overcome workplace challenges and at the other hand to
develop interventions to enhance sustainable employability.
CHRONIC HEALTH CONDITIONS
Chronic health conditions typically begin in middle age7,22,23 and have an adverse impact
on the employability of workers24‐26. An increase in chronic health conditions has been
recognized as a feature of the demographic and epidemiological transitions in our
population over the last century22,23,27.
In the Netherlands, 37% of workers reported a chronic health condition and about 20% of
those workers were hampered in the performance of their work28,29. Given the fact that
the prevalence of chronic health conditions generally increases with age, and that workers
will be required to work until they are older due to the ageing population, the prevalence
of chronic health conditions in the work place can be expected to increase even further in
the coming decades7,30. In 2011, it was expected that male workers of 45 years of age will
live for another 36 years, of which 12 will be without a chronic health condition, while
female workers of 45 years of age can expect to live for another 39 years, of which 13 will
be free of chronic health conditions. This implies that in the last ten years of their working
life half of the workers have to deal with a chronic health condition.
Multimorbidity, defined as ‘the co‐occurrence of multiple chronic conditions or acute
disease and medical conditions within one person31 is also a growing concern. Previous
studies have shown that workers with a chronic health condition, depending upon the
condition, experienced difficulties in meeting the physical and psychosocial demands of
their job32. To gear work demands and activities to the personal capabilities of a worker to
ensure they remain employable in the coming decades requires a strategy for workers
with a chronic health condition. This strategy should assist them to solve problems
General introduction
13
associated with their working life, giving them the confidence in their ability to effectively
carry out actions which ensure their sustainable employability33,34.
INCREASING SUSTAINABLE EMPLOYABILITY OF AGEING WORKERS
The changing situation of the workforce as outlined above endorse the necessity of
attention to sustainable employability on macro‐ (e.g. pension adequacy and income
maintenance), meso‐ (e.g. personnel policy which provide resources for career
perspectives), and micro level (e.g. the workers’ health). The challenge is to keep the
relatively large group of ageing workers motivated and employable, and this should be
accomplished without threatening the wellbeing. To keep workers in the labour market
during the coming decades, employers should invest in the implementation of policies,
education on the job and working methods to enable workers to have the necessary
competencies for longer working lives2,35.
During last decades, the nature of work has changed due to globalization and information
technologies and work‐based life‐long learning is required to maintain and enhance
employable36. Moreover, the more dynamic market and shorter product cycles have
resulted in fewer jobs, with frequent job changes over a working lifetime. Due to these
changes in the labour market, the worker‐employer relationship has evolved from one of
mutual loyalty to one based on mutual gain, but with personal responsibility of the
worker. Workers are increasingly responsible for their own career, and they need to be
aware of their own responsibility and decisive role in creating and/or maintaining a
healthy work life. To encourage workers to control their own employability until
retirement, the development of an intervention is necessary which offers a strategy to
identify problem, challenges, and solutions to increase the workers’ problem solving
capacity towards sustainable employability.
Up until now, most intervention studies to promote workers’ health to extend working life
provide workplace interventions for specific group of workers, to improve job retention 37,
increase vitality38 or decrease work disability and sickness absenteeism39‐42. However, to
gear the work demands and activities to the personal capacities of the ageing worker, a
strategy to solve problems with regard to ageing and chronic health conditions is required.
As a preparatory step toward developing such an intervention, the specific characteristics
of the target group need to be assessed. More specifically, the needs and determinants of
the target population should be gathered43. Next important steps are the development
and evaluation of the intervention.
Chapter 1
14
OBJECTIVES OF THIS THESIS
The objectives of this thesis are:
1. To provide insight into the needs and determinants regarding a sustainable
working life among workers aged 45 years and older, with and without chronic
health conditions;
2. To develop and evaluate an intervention aimed at enhancing sustainable
employability.
Based on a literature study1,44‐46, ageing workers in this thesis are defined as ‘workers aged
45 years and older’. The presence of a chronic health condition is defined as ‘the
subjective experience of a long‐term irreversible disease of more than 3 months duration’,
which is in accordance with the definition used in many other studies47,48.
OUTLINE
Chapter 2 describes the workers’ perspectives on the problems experienced due to
ageing, obstacles to performing work tasks due to ageing, retention factors that ensure
work participation, and support needs required to continue working in the coming years
for workers with and without a chronic health condition. The type and number of
problems experienced, the obstacles, the retention factors and the needs are presented.
An in‐depth research approach was chosen as it offers a deeper understanding of
perceived motives and factors associated with maintaining work participation. In
Chapter 3, the relationship between chronological and functional age is determined, and
the association between chronological age and functional age and five work outcomes is
examined: work ability, problems, obstacles, retention factors and needs due to ageing. In
Chapter 4, the influence of work conditions, psychosocial determinants and perceived
health is determined in relation to the association between a chronic health condition and
work ability. Variables associated with work ability are examined separately for workers
with and without a chronic health condition. Chapter 5 focuses on the association
between different coping strategies and work ability and the modifying effect of job
control and emotional and instrumental support for ageing workers. In addition,
differences between workers with and without a chronic health condition are determined.
Chapter 6 describes the study design of the intervention ‘Staying Healthy at Work’.
Chapter 7 presents the effectiveness and process evaluation of the intervention ‘Staying
Healthy at Work’, and Chapter 8 provides a general discussion. The main findings of this
thesis are summarized and discussed, methodological considerations are addressed and
the recommendations for future use of the intervention, and for policy and practice are
presented.
General introduction
15
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based health education programs. Health Educ Behav 1998;25:545‐563.
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workers' lifestyle and vitality‐related outcomes: results of a randomised controlled trial. J Epidemiol
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45. Jedryka‐Goral A, Bugajska J, Lastowiecka E, et al. Work ability in ageing workers suffering from chronic
diseases. Int J Occup Saf Ergon 2006;12:17‐30.
46. Ageing at work: consequences for industry and individual. Lancet 1993;341:87‐88.
47. Beatty JE, Joffe R. An overlooked dimension of diversity: The career effects of chronic illness. Organ Dyn
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48. De Klerk MMY. Rapportage gehandicapten 2000: arbeidsmarkt en financiële situatie van mensen met
beperkingen en/of chronische ziekten [Report of the handicapped 2000: employment and financial
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2000.
2
In‐depth study of the workers’ perspectives to enhance
sustainable working life: comparison between workers with
and without a chronic health condition
J Occup Rehabil. 2013 Jun;23(2):170‐9
W. Koolhaas
J.J. van der Klink
J.P. Vervoort
M.R. de Boer
S. Brouwer
J.W. Groothoff
Chapter 2
20
ABSTRACT
Purpose: To gain in‐depth understanding of the number and type of experienced ageing
problems, obstacles to perform work tasks, retention factors to maintain work and
support needs to continue working life in the next years among workers aged 45 years and
older with and without a chronic health condition.
Methods: A survey of workers’ perspectives on problems, obstacles, retention factors and
needs due to ageing was carried out in 3008 workers aged 45 years and older in nine
different companies. To classify the open‐ended questions we used the International
Classification of Functioning and disability (ICF).
Results: Older workers with a chronic health condition reported more problems due to
ageing (56% vs 34%; p<.001), more obstacles (42% vs 16%; p<.001) and more needs (51%
vs 31%; p<.001) compared to those without a chronic health condition. No relevant
differences were found on type of experienced problems, obstacles, retention factors and
needs between both groups. Problems and obstacles were found on physiological and
psychological functions. Retention factors and needs to enhance sustainable working life
were particularly reported on work‐related environmental factors.
Conclusion: Because workers with a chronic health condition experienced more problems,
obstacles and needs, the largest gain of occupational intervention can be achieved in
these workers. However, our findings suggest that interventions aimed to enhance
sustainable working life of older workers can be similar in content for persons with and
without chronic health conditions and should have a central focus on work‐related factors.
Keywords: Ageing problems, Chronic health condition, Obstacles and retention factors,
Support needs, Sustainable working life, Workers’ perspectives
Workers’ perspectives to enhance sustainable employability
21
INTRODUCTION
Because of the ageing population, employers will be confronted with manpower in which
older workers are represented more strongly than before1. Enabling and encouraging
older workers to remain on the labour market is important. Mobilising the full potential of
older people is a key response to those demographic changes, which require the
promotion of a healthy working life2. However, the process of ageing burdens on physical
and mental health status3 and is significantly associated with a decreased work ability4 and
early discontinuation of working life5,6. Due to the aging population, an increase of the
incidence of chronic health conditions in the working population is expected in the next
twenty years. Perceived health declines with age, and the prevalence of chronic health
conditions increases after the age of 45 years7,8 and have an adverse impact on the
employability of the older workers9,10. The higher prevalence of chronic health conditions
is in turn strongly related to more ‘fatigue’ and ‘emotional exhaustion’, which are
correlated with perceived work stress11,12. Thus, deterioration in health status due to
ageing will make workers more vulnerable in the labour process.
The increase in problems due to ageing as well as health related problems from the age of
45 years onwards implies the importance of attention to obstacles and retention factors
for maintaining or enhancing a sustainable working life. Several prognostic studies have
identified problems and risk factors associated with sustainable employability for ageing
workers in general13‐16. However, little is known about the workers’ perspectives on
obstacles, retention factors and support needs with regard to continuing their working
life. There have been some studies on obstacles and motivators in the work situation from
a patients’ perspective or workers with health conditions, but these have been conducted
in specific populations12,17,18. In addition, several studies have shown that the presence of
a chronic condition has impact on work ability3,19, work disability8 and productivity9.
Therefore it is conceivable that the number and type of problems, obstacles, retention
factors and needs differ between workers with and without a chronic health condition.
Insight into these factors is an important next step towards the development of strategies
and (preventive) measures aimed at addressing the potential workforce shortages in daily
practice.
The aim of the present study is to compare the number and type of experienced
problems, obstacles, retention factors and support needs among workers aged 45 years
and older with and without a chronic health condition.
Chapter 2
22
METHODS
The data of this cross‐sectional in‐depth survey study were obtained from workers aged
45 years and older. Nine companies in the northern part of the Netherlands, invited by
their occupational health physicians, were willing to participate in the study. Three large
size companies (≥1000 workers), two medium sized companies (≥500 workers) and four
small companies (<500 workers) participated. These companies represented four sectors:
health care (two companies; n=4097), education (3 companies; n=3167), government (1
company; n=563) and industry (3 companies; n=590). A self‐administrated questionnaire
including an information letter about the study with instructions on how to fill in the
questionnaire was send to all workers aged 45 years and older of the nine companies (n =
8417). All companies enclosed a letter of recommendation. The anonymity of respondents
and confidentiality of the information they provided were guaranteed. Four weeks after
the initial mailing, all workers received a written reminder. The data were collected in
February and March 2008.
Ethical approval was sought from the Medical Ethics Committee of the University Medical
Center Groningen, which advised that, according to Dutch law, ethical clearance was not
required for this study.
Measures
We used self‐constructed dichotomous (yes/no) questions and open‐ended questions. The
first question assessed whether the workers experienced ageing problems: ‘Do you
encounter problems in working life due to ageing?’. The next two questions concerned the
obstacles and retention factors for continuing working life: ‘Do you experience obstacles
in performing work tasks due to ageing problems?’ and ‘Are there factors in your work
which facilitate you in maintaining a sustainable working life?’. The fourth question was
about the support needs to continue working life in the coming years: ‘Do you need
support in the work situation to continue working life in the coming years despite
ageing?’. For each question with a ‘yes’ answer, the workers were asked to report a
maximum of the three most important examples which were on top of their mind.
Additionally, the questionnaire included questions about: age, gender, education,
occupation, sector and whether the worker experienced a chronic health condition.
Education was categorized into no education/primary school, lower vocational education,
intermediate secondary and vocational education, higher vocational education and
university and other or unknown. Occupation was divided into four groups: executive,
secretarial, policy and management. In accordance with many other studies, a chronic
health condition was defined as ‘the subjective experience of long‐term irreversible
Workers’ perspectives to enhance sustainable employability
23
disease of more than 3 months duration’20,21. It was assessed by asking the respondents
the following question: ‘Do you currently have a long‐term or chronic health condition of
more than 3 months duration without the prospect of recovery?’(yes/no).
Classification system
To classify and compare the workers’ perspectives we used the International Classification
of Functioning, Disability and Health (ICF)22. The ICF is a classification of human functioning
and disability developed by the World Health Organisation to systematically categorize
health and health‐related states as well as contextual factors that may impact those
states22. It offers a taxonomy for the classification of functions, structures, activities,
participation and a list of external factors. The ICF does not contain a taxonomy for work‐
related external factors and no consensus has been reached for a list of personal
factors23,24. Therefore, we used the expanded classification as described by Heerkens et al.
to classify the work‐related external factors23. For the personal factors we used the update
of the provisional list of personal factors as described in the Newsletter on the WHO
Family of International Classifications24.
Classifying data
To link the data to the ICF codes, the updated linking rules developed by Cieza et al. were
used25,26. Following the linking rules, the open ended data was linked to the most
appropriate corresponding ICF category, identified with its unique alphanumeric codes
that indicate the components of the ICF: ‘Body functions’ (B), ’Body structures’ (S),
‘Activities and participation’ (D), ’Environmental factors’ (E). For classifying the ‘Work‐
related environmental factor’ and ’Personal factors’ we used the alphanumeric codes ‘W’
and ‘P’ respectively. In each classified component of the ICF, the categories are arranged
in a stem‐branch‐leaf scheme. Consequently, a higher level (more detailed) category
shares the lower‐level categories of which it is member. Classification of the data in this
study took place on the highest level available of the ICF components (mostly fourth or
fifth). If the example reported by the workers did not provide sufficient information to
make a decision about the most precise ICF category, the concept was deemed not
definable and was assigned the code Nd (Not defined). When not definable answers
referred to a health condition we used Nd‐hc (Not defined‐health condition). If an answer
described an aspect, which was not covered by the expanded ICF, it was assigned Nc (Not
covered)25.
We conducted a pilot to test the usability of the ICF in the current study. Two practising
occupational health physicians, all familiar with the ICF, and the first author (WK)
Chapter 2
24
categorised a random sample of 200 workers independently, and compared and discussed
their results. In case of disagreement (16%), differences were discussed until consensus
was reached. During the pilot we developed a short list of the relevant ICF‐codes in our
study. During the pilot we developed a short list of the relevant ICF‐codes in our study. In
addition, the usability of the additional stem‐branch‐leaf scheme for the ‘Work‐related
environmental factors’ and ’Personal factors’ was tested. An short example of the list of
classification codes used in this study is shown in Table 1. The complete list used in this
study can be obtained from the authors. Two authors (WK, JV) categorised all data. They
categorised 30% independently and compared their results, to minimize the risk of bias.
Data analyses
A description of the socio‐demographic characteristics was given by frequencies, standard
deviations, means and percentages for the total sample and for both groups of workers
with and without chronic health conditions. To estimate differences between both groups
the t‐test was used for the continue variable age. The chi‐square statistics was used for
the categorical variables. We examined the differences in proportion of persons
experiencing problems, obstacles, retention factors and needs between workers with and
without a chronic health condition by using logistic regression. We adjusted the analysis
for gender and occupation.
The number and type of problems due to ageing, obstacles, retention factors and needs to
continue work and the ICF codes identified were given by frequencies and percentages for
workers with and without chronic health conditions separately. The different problem,
obstacle, retention and need items were summated over the respondents and the top 10
most frequently reported were presented. All analyses were carried out with the
statistical package SPSS version 20.0 (IBM Corp. Released 2011. IBM SPSS statistics.
Armonk, NY).
Workers’ perspectives to enhance sustainable employability
25
Table 1: Example of the list of classification codes between the self‐reported answers and corresponding ICF components including the work‐related external factors and personal factors
ICF codea ICF category title
1st level 2nd level 3rd level 4th level
B1 MENTAL FUNCTIONS
B140 Attention functions
B1400 Sustaining attention
B144 Memory functions
B1441 Long‐term memory
B2 SENSORY FUNCTIONS AND PAIN
B210 Seeing functions
B2100 Visual acuity functions
B280 Sensation of pain
B2801 Pain in body part
B28010 Pain in head and neck
B28013 Pain in back
D4 MOBILITY
D415 Maintaining a body position
D4152 Maintaining a kneeling position
D4153 Maintaining a sitting position
D4154 Maintaining a standing position
D7 INTERPERSONAL INTERACTIONS AND
RELATIONSHIPS
D740 Formal relationships
D7400 Relating with persons in authority
D7401 Relating with subordinates
D7402 Relating with equals
E2 NATURAL ENVIRONMENT AND HUMAN‐MADE
CHANGES TO ENVIRONMENT
E225 Climate
E2250 Temperature
E2251 Humidity
P PERSONEL RELATED ENVIRONMENTAL
FACTORS
P100 Socio‐demographic factors
P1010 Age
P1020 Gender
P1030 Education
P1040 Partnership/marriage
Chapter 2
26
Table 1: continued
ICF codea ICF category title
1st level 2nd level 1st level 2nd level
P1050 Income
P500 Work related personal
P5010 Occupation/profession
P5020 Occupational status
P5030 Commitment to work
P5060 Work history
P5110 Need for work
P5120 Success
W WORK‐RELATED ENVIRONMENTAL FACTORS
W100 Work content
W1010 Job tasks
W10101 Supervising colleagues
W10102 Delegating tasks
W10103 Tasks reduction
W1020 Skills required
W1030 Decision authority
W500 Organisation
W5010 Organisation culture
W50101 Manners
W50102 General attitude towards absenteeism
W5010 Company type
a The complete list used in this study can be obtained from the authors
Workers’ perspectives to enhance sustainable employability
27
RESULTS
Out of the 8417 workers aged 45 and older who were invited to participate in the study,
3008 returned the self‐administered questionnaire. The mean response rate was 36% and
varied for the nine companies between 28% in a large health care company and 58% in
one small company in the industrial sector. We excluded 25 workers from the study
because of missing data on experienced problems, obstacles, retention factors or needs. A
description of the socio‐demographic characteristics is presented in Table 2. The mean age
of the workers was 53.4 years (SD 5.0) ranging from 45 to 64 years. Fifty‐one per cent of
the workers was female, and 60% was working in an executive occupation. Most workers
were highly educated (59%) and most of them were working in the sectors education
(42%) and health care (41%). Thirty‐seven per cent (n=1109) of the workers reported the
presence of a chronic health condition. Significant differences for workers with and
without a chronic health condition were found on gender and occupation. The percentage
of female workers was higher in workers with a chronic health condition. Workers in
executive (40%) and secretarial/administrative (41%) functions reported more chronic
health conditions than policy workers (32%) and management (29%).
Comparison of the experienced problems, obstacles, retention factors and support
needs
In the total sample, 1246 (42%) of the workers reported problems due to ageing, 763
(26%) reported obstacles to perform work due to ageing problems, 2451 (82%)
experienced retention factors maintaining a sustainable working life and 1142 (38%)
reported that they had special support needs to continue their working life in the coming
years (data not shown). Workers with a chronic health condition reported significantly
more problems due to ageing (56% vs 34%; p<.0001), more obstacles to perform work due
to ageing problems (42% vs 16%; p<.0001) and more support needs to continue their
working life in the next coming years (51% vs 31%; p<.0001) compared to workers without
a chronic health condition. The mean number of problems, obstacles and needs reported
per person were higher for workers with a chronic health condition compared to workers
without a chronic health condition, i.e. problems due to ageing (1.88 vs 1.74), obstacles
(1.93 vs 1.62) and support needs (1.51 vs 1.41). No difference was found between both
groups for the experienced retention factors (see Table 3).
28
Table 2: C
haracteristics and number of experienced problems, obstacles, reten
tion factors and needs
Total sam
ple
(n=2983)
Workers with a chronic health
condition (n=1109; 37%)
Workers without a chronic
health condition (n=1874)
n=2983
n
%
n
%
n
%
Mean age (SD
)
53.4 (5.0)
53.5 (4.8)
53.3 (5.0)
Female workers a
1527
51
621
56
906
48
Education
No education/ Primary school
52
2
21
2
31
2
Lower vocational education
451
15
181
16
270
14
Interm
ediate secundary and vocational education
707
24
264
24
443
24
Higher vocational education and university
1761
59
638
58
1123
60
Other or unknown
12
<1
5
<1
7
<1
Sector
Health care
1213
41
466
42
747
40
Education
1267
42
469
42
798
43
Production
231
8
98
9
174
9
Governmen
t 272
9
76
7
155
8
Occupationa
Executive
1786
60
708
64
1078
58
Secretarial / Administrative
375
13
152
14
223
12
Policy
385
13
123
11
262
14
Managem
ent
398
13
115
10
283
15
Unkown
39
1
11
1
28
1
a Chi‐square statistics shows significant differences between workers with and without a chronic health condition (p<.001)
29
Table 3: The number and type of reported
examples of the workers’ perspectives of problems, obstacles, reten
tion
factors and needs linked to ICF codes for workers with a chronic health condition
Workers with a chronic health condition (n=1109)a
Problems
Obstacles
Retention
factors
Needs
Number of workers who reported yes (%
)617 (56)
465 (42)
910 (82)
560 (51)
Mean (SD
) number of reported
per worker (Total
reported
/N (yes))
1.88 (0.82)
1.93 (0.83)
2.00 (0.84)
1.51 (0.74)
Reported answ
ers on the IC
F components
b
B Body functions
834
71
284
32
6<1
7<1
S Body structure
0‐
0‐
0‐
0‐
D Activities and Participation
80
7
262
29
449
24
37
4
E Environmen
tal factors
6<1
0
‐4
<13
<1
P Personal factors
6<1
9
<1302
16
16
2
W W
ork‐related
factor
177
15
331
37
1078
58
776
92
Not definable‐Health conditions
54
5
6<1
0‐
0‐
Not definable
6<1
4
<18
<15
<1
30
Table 3: continued
(for workers without a chronic health condition)
Workers without achronic health condition (n=1874)a
Problems
Obstacles
Retention
factors
Needs
Number of workers who reported yes (%
)629 (34)
298 (16)
1541 (82)
582 (31)
Mean (SD
) number of reported
per worker (Total
reported
/N (yes))
1.74 (0.80)
1.62 (0.79)
2.00 (0.83)
1.41 (0.69)
Reported answ
ers on the IC
F components
b
B Body functions
813
74
191
39
14
<11
<1
S Body structure
0‐
0‐
0‐
0‐
D Activities and Participation
66
6
92
19
752
24
26
3
E Environmen
tal factors
4<1
0
‐6
<12
<1
P Personal factors
13
1
0‐
467
15
6<1
W W
ork‐related
factor
186
17
196
40
1879
60
780
95
Not definable‐Health conditions
4<1
2
<10
‐0
‐
Not definable
2<1
3
<111
<17
<1a Logistic regression analyses, adjusted
for gender and occupation, shows significant differences betw
een experien
ced
problems due to ageing (p<.001), obstacles to perform
work (p<.001), and support needs continue their working life in
the next
coming years (p<.001) between workers with and without a chronic health condition
b W
orkers were asked
to rep
ort a m
axim
um of the three most im
portant exam
ples of these factors which were on top of their mind
Workers’ perspectives to enhance sustainable employability
31
Classification of the workers’ perspectives
After linking the data to the components of the ICF (Body functions, Body structures,
Activities and Participation, Environmental factors) the percentages of reported answers
on the ICF components showed similar results for workers with and without a chronic
health condition (CHC) (Table 3). The most experienced problems due to ageing were
reported on the ICF component ‘Body functions’ (with CHC: 71% vs without CHC: 74%),
followed by work‐related factors (15% vs 17%) and ‘Activities and Participation’ (7% vs
6%). Problems on the other ICF components were hardly reported. The most experienced
obstacles to perform work were reported least often on the ICF components ‘Work‐
related environmental’ (with CHC: 37% vs without CHC: 40%), ‘Body functions’ (32% vs
39%) and ‘Activities and Participation’ (29% vs 19%). The components ‘Work‐related
environmental’ (with CHC: 58% vs without CHC: 60%), ‘Activities and Participation’ (24% of
both groups), and ‘Personal factors’ (16% vs 15%) were reported as retention factors to
maintain a sustainable working life. Support needs to continue working life were
particularly reported on the component ‘Work‐related environmental factors’ with 92%
and 95% respectively for both workers with and without a chronic health condition.
The most frequently reported problems, obstacles, retention factors and needs were
similar for workers with and without a chronic health condition (see Table 4). Most
frequently experienced problems due to ageing were problems with energy level, recalling
information stored in long‐term memory and bringing it into awareness (retrieval of
memory), functions related to sustaining muscle contraction of all muscles of the body for
the required period of time (endurance of all muscles of the body) and the seeing function
for both distant and near vision (visual acuity functions). The most frequently reported
obstacles to perform work due to ageing problems were tasks which require
concentration for the period of time required (sustainable attention), lifting and carrying
object, working schedules and work pace. The most frequently reported retention factors
to maintain a sustainable working life were: creating and maintaining formal relations with
people in the same position (relating with equals), beginning and maintaining interactions
with others for a short or long period of time (forming relationships), job tasks and
creating and maintaining formal relations with people in positions of lower rank or
prestige relative to one's own social position (relating with subordinates). The most
frequently reported support needs to continue working life in the next coming years were
working less hours, tasks reduction, reducing time pressure, improvement of the physical
conditions in the work place and ergonomic adjustments (see Table 4).
32
Table 4: Top 10 of the most frequen
tly reported
type of ageing problems, obstacles, reten
tion factors and needs to continue
work of workers with and without a chronic health condition
Workers with a chronic health condition
Workers without a chronic health condition
ICF Code
Freq
%
Item
ICF Code
Freq
%
Item
Problems due to ageing
Total number reported n=1163
Total number reported n=1093
B1300
196
17
Energy level
B1300
207
19
Energy level
B7402
87
7
Endurance of all m
uscles of the body
B1442
100
9
Retrieval of mem
ory
B1442
76
7
Retrieval of mem
ory
B2100
72
7
Visual acuity functions
B7152
64
6Stability of joints generalized
B7402
70
6Endurance of all m
uscles of the body
B1400
53
5
Sustaining attention
B7800
40
4
Sensation of muscle stiffness
B2100
46
4
Visual acuity functions
B1400
38
3
Sustaining attention
B7800
41
4Sensation of muscle stiffness
W1101
36
3Men
tal dem
ands –obtaining and
using new
knowledge
B28013
40
3
Pain in
back
B28013
33
3
Pain in
back
W1101
30
3Men
tal dem
ands ‐obtaining and using
new
knowledge
B7152
32
3Stability of joints generalized
B1643
24
2Cognitive flexibility
B6702
29
3Discomfort associated
with
men
opause
33
Table 4: continued
(obstacles)
Workers with a chronic health condition
Workers without a chronic health condition
ICF Code
Freq
%
Item
ICF Code
Freq
%
Item
Obstacles to perform
work due to ageing
Total number reported n=896
Total number reported n=484
B1400
134
15
Sustaining attention
B1400
89
18
Sustaining attention
D430
107
12
Lifting and carrying objects
W1080
45
9
Work pace
W3012
59
7
Working sched
ules
W3012
44
9
Working sched
ules
W1080
58
6
Work pace
D430
40
8
Lifting and carrying objects
W1010
57
6
Job tasks
W1010
24
5
Job tasks
B1300
37
4
Energy level
W3013
19
4
Shift work
W4011
24
3
Time pressure
B1300
13
3
Energy level
W3013
23
3
Shift work
B1442
13
3
Retrieval of mem
ory
W1101
22
2Men
tal dem
ands ‐obtaining and using
new
knowledge
W1200
12
2Men
tal dem
ands ‐obtaining and using
new
technologies
D4154
22
2
Maintaining a standing position
B2100
11
2
Visual acuity functions
34
Table 4: continued
(retention factors)
Workers with a chronic health condition
Workers without a chronic health condition
ICF Code
Freq
%
Item
ICF Code
Freq
%
Item
Retention factors to m
aintain working life
Total number reported n=1847
Total number reported n=3129
D7402
322
17
Relating with equals
D7402
498
16
Relating with equals
D7200
157
9
Form
ing relationships
D7200
269
9
Form
ing relationships
W1010
139
8
Job tasks
W1010
217
7
Job tasks
D7401
131
7Relating with subordinates
W1101
196
6Men
tal dem
ands ‐obtaining and using
new
knowledge
P5050
117
6
Job satisfaction
D7401
198
6
Relating with subordinates
D7101
99
5
Appreciation in
relationships
D7101
168
5
Appreciation in
relationships
W1050
92
5
Autonomy
W2060
166
5
Work atm
osphere
W1101
82
4Men
tal dem
ands ‐obtaining and using
new
knowledge
P5050
165
5Job satisfaction
W2060
80
4
Work atm
osphere
W1050
150
5
Autonomy
P2060
72
4
Purpose in
life
W1060
115
4
Variation job tasks
35
Table 4: continued
(needs)
Workers with a chronic health condition
Workers without a chronic health condition
ICF Code
Freq
%
Item
ICF Code
Freq
%
Item
Needs of support to continue working life in
the next coming years
Total number reported n=844
Total number reported n=822
W1013
95
11
Tasks reduction
W3015
109
13
Working hours
W3015
87
10
Working hours
W1013
76
9
Tasks reduction
W4011
67
8
Time pressure
W4020
51
6
Physical conditions work
W4031
50
6
Ergonomic conditions ‐ furniture
W4011
50
6
Time pressure
W4020
48
6Physical conditions work
W4034
47
6Ergonomic conditions ‐tools and
machinery
W4034
39
5Ergonomic conditions ‐tools and
machinery
W3013
45
5Shift work
W5061
28
3
Policy of company
W4031
37
5
Ergonomic conditions ‐ furniture
W3013
24
3
Shift work
W3011
28
3
Working hours
W3012
20
2
Working sched
ules
W5010
24
3
Organisation culture
W4030
19
2
Ergonomic conditions
W5061
24
3
Policy of company
Chapter 2
36
DISCUSSION AND CONCLUSION
Our study shows that older workers with a chronic health condition experience more
problems due to ageing, more obstacles to perform work and more needs to continue
working life compared to older workers without chronic health conditions. Most problems
due to ageing were linked to the ICF component ‘Body functions’ (B) which covers
physiological functions of body systems, including psychological functions. Perceived
obstacles to perform work due to ageing problems were mainly related to the ICF
components ’Body functions’ (B), ’Activities and participation’ (D) and ’Work‐related
environmental factors’ (W). Retention factors for maintaining a sustainable working life
and support needs to continue working life in the next coming years, were particularly
reported on ‘Work‐related environmental factors’ (W). Relevant differences in type of
reported problems, obstacles, retention factors and needs with respect to enhance
sustainable working life between workers with and without chronic health conditions
were not found.
In the past few years several studies have demonstrated that health status has a
profound impact on the ability of workers to be actively engaged in paid employment and
to prolong their meaningful contribution to a productive society3,4,13. There is evidence
from longitudinal studies that poor health, in particular self‐perceived poor health, plays a
role in exit from paid employment27‐29. Our findings that workers with chronic conditions
experience more problems and obstacles and reported more support needs emphasize
the vulnerability of this specific group of older workers and their need for preventive
occupational interventions.
We found no large differences between workers with and without a chronic
health condition with respect to the type of experienced problems, obstacles, retention
factors and needs. Previous studies focussed on understanding why older workers
continue to work and the obstacles and retention factors they encounter are mostly based
on specific perspectives. These studies showed perceived perceptions of constraints of
older workers (>60 years)30‐32, the ability to carry on working in specific occupations13,16, or
working with (specific) chronic health conditions12,18,33,34. Differences between workers
with and without a chronic health condition we found in literature were addressed to
fatigue, emotional exhaustion and perceived health complaints11. Qualitative or in‐depth
studies from the workers’ perspectives of experienced types of ageing problems,
obstacles, retention factors and needs in working life to compare with our results are
scarce. Moreover, data about differences between workers with and without a chronic
health condition of relevant factors from the workers’ viewpoint to enhance sustainable
working life were not found. That we found no differences in types of problems, obstacles,
Workers’ perspectives to enhance sustainable employability
37
retention factors and needs between workers with and without a chronic health condition
might suggest that preventive occupational interventions do not need to differentiate
between workers with and without a chronic health condition.
The importance of the components ‘Body function’ and ‘Work‐related
environmental factors’ was in line with our expectations. Ageing has been found to be
strongly related to a decrease in physical and cognitive functioning3,35,36. Good health and
physical fitness were perceived to be facilitators to work participation from the workers’
point of view31,32. In addition, prognostic studies focussing on different working
populations or health conditions have shown that work related adjustments such as
reducing work hours, changing the type of work, reducing physical demands and work
stress were relevant factors to maintain work participation12,13,37. This study shows that
most workers are aware that their problems due to ageing mainly concern ‘Body
functions’. However, they assume that the burden of these ageing problems will not
disappear and that adjustments in the work situation are necessary to enhance
sustainable working life. In line with this they report work‐related retention factors and
needs to remain and continue work participation. With respect to preventive occupational
interventions this suggest that workers at risk could be identified by their problems on
‘Body functions’, but that the intervention must focus on creating a balance between
workload and the workers individual capacity.
As many problems, obstacles, retention factors and needs are named by the
participants in this study, the results do not indicate a specific intervention. Nor do the
results support the development of different interventions for workers with and without a
chronic health condition. Most experienced problems are reported on the ICF component
‘Body Function’, but the impact of those problems on obstacles to perform work were
different from the workers’ perspectives. Obstacles were reported on the ICF components
‘Body Functions’, ‘Activities and Participation’ as well as ‘Work related factors’. Support
needs to continue work were particularly reported on the ICF component ‘Work‐related
factors’. However, the requested adjustment were spread on different work‐related
factors. Thus, a preventive intervention to overcome the challenge of an ageing workforce
should be tailor‐made and able to deal with individually experienced problems and needs.
From previous research we know that empowerment and self‐management interventions
could contribute to a sustainable working life for both workers with and without a chronic
health condition38,39. It is also known that supervisors are most likely to receive the first
request for accommodations from workers and are responsible for facilitating these
workers40,41. Therefore, important elements of such a preventive and tailor‐made
intervention should base on: a) an inventory of (work‐related) problems, obstacles and
Chapter 2
38
personal development opportunities, and b) the possibility to discuss work‐related
environmental factors and adaptations based on the individual worker. A booklet for
workers to encourage a structured dialogue with the supervisor to identify the
experienced problems and to explore possible solutions of the worker, might be a useful
starting point for a tailor‐made and effective intervention in which both the worker and
the supervisor can take their responsibility. Such an intervention is focussed on increasing
the problem‐solving capacity of the workers and stimulating their awareness of their role
and responsibility towards a healthy working life, with support of the supervisor.
A strength of our study is that we used open ended questions to give as much
room as possible to the workers’ own perspective on their problems due to ageing,
obstacles and retention factors in work participation and needs to continue working life.
This design elucidates data from the experiences of the workers themselves, because the
questions were not directed towards a number of set answering categories. The open‐
ended questions enabled authentic themes to be named, independent from prevailing
constructs, instruments, or questionnaires, and thus give an in‐depth overview. However,
this study is not a qualitative study, but an in‐depth study of the workers’ perspectives on
problems, obstacles, retention factors and needs to increase sustainable work.
Subsequently, the data was categorised by using the framework of the ICF model. The ICF
proved highly useful for the content comparison of the workers’ perspectives of the open‐
ended data. Expanding the ICF classification by using a list of work‐related environmental
factors and personal factors as well was helpful. However, in a future revision of the ICF
component ‘Work‐related environmental factors’ the classification of job tasks could be
more specified (e.g. tasks reduction, supervising colleagues, teamwork) and aspects
referring to ‘working at home’ should be included.
A limitation of this study is that the overall response rate of 36% at baseline could
have led to selective participation. Because of the anonymous study design, we were not
able to investigate the characteristics of the non‐responders properly. The results of our
study might not be representative for workers in the production sector because of the
underrepresentation of these workers in our study. Nevertheless, we believe there is no
reason to expect that workers with problems due to functional age or a chronic health
condition returned the questionnaire less frequently than workers without problems. The
questionnaire addressed a variety of themes, and did not emphasize functional age or
chronic health conditions. Another potential limitation is that the current study does not
distinguish between specific chronic health conditions because of the lack of knowledge of
the severity and limitations of the conditions. It is possible that severely ill and chronically
Workers’ perspectives to enhance sustainable employability
39
disabled are in most cases excluded from working life and their perspectives are not
included in our sample. The workers who are still working, might be a select, relatively
healthy group of the general population of this age. Because of this selection bias due to
the healthy worker effect, the results in this report are probably an underestimation of
the problems in the entire age group42,43.To make no difference between workers
suffering from various chronic health conditions in relation to a sustainable working life is
supported by Detaille et al. among physically ill workers18,44. They showed that different
groups of chronically ill workers were experiencing the same themes that they perceived
to be important for continuing their work, although their priority varied. Finally, this study
is an in‐depth study using open ended questions, but it is not a qualitative study involving
material derived from interviews or observation. Defining and judging the open ended
data was sometimes difficult because the context for interpretation was missing.
However, to control for the quality of the information gathered, a two step‐method was
used. First, we conducted a pilot study. In a further attempt to minimize the risk of bias,
an additional 30% of the data were analysed independently by two authors. We assume
that the opportunity to gain in‐depth information of the workers’ perspectives of a large
group of workers in different occupations and organisations is more valuable than using
predefined constructs or a small set of qualitative data. Moreover, because of the
complementary knowledge of the investigators and the generally clear description of the
open‐ended answer, we do not expect that the method used in this study has led to a
distorted picture.
In conclusion, older workers with a chronic health condition reported significantly more
problems due to ageing as well as obstacles to continue their working life and support
needs to continue work in the upcoming years, compared to workers without a chronic
health condition. However the type of problems, obstacles, retention factors and support
needs were very similar, with problems mostly related to bodily functions, and retention
factors and needs mostly related to work‐related factors. These findings suggest that
interventions aimed to enhance sustainable working life of older workers can be similar
for persons with and without chronic health conditions and should have a central focus on
work‐related factors.
Chapter 2
40
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3
Towards a sustainable healthy working life: associations
between chronological age, functional age and work outcomes
Eur J Public Health. 2012 Jun;22(3):424‐9
W. Koolhaas
J.J. van der Klink
J.W. Groothoff
S. Brouwer
Chapter 3
44
ABSTRACT
Background: The aims of this study were a) to determine the relation between chronological and functional age; b) to examine the association between chronological age and work outcomes; and c) to examine the association between functional age and work outcomes. An overview of the most reported work outcomes is outlined. Methods: Chronological age refers to the calendar age; functional age was measured with perceived health status (SF‐36) and the presence of a chronic health condition. Perspectives on experienced problems, barriers, facilitators and support needs due to ageing and the Work Ability Index were gathered out as work outcomes. Results: The association of chronological and functional age of workers aged 45 years and older (n=2971) on work outcomes were significant but small, except for the presence of a chronic health condition. The presence of a chronic health condition was not related to chronological age. Older workers (60‐64 years) reported better scores on social functioning, mental health and vitality compared to workers aged 45‐59. Most reported problems due to ageing were energy decline, muscle function decline, concentration lapses and memory deterioration. Experienced barriers were concentration, work pace problems, and mobility; facilitators were support from colleagues, informal relations at work and supervisors. Individual agreement had to be met to continue working life. Conclusions: This study confirmed that both chronological and functional age were associated with a decrease in work outcomes. Workers above 60 did not experience more problems and barriers compared to workers between 45‐49 years of age. Key terms: Chronological age, functional age, older worker, chronic health condition,
sustainable healthy work participation
Chronological age, functional age and work outcomes
45
INTRODUCTION
The growing proportion of older people in the labour force stresses the need to promote a
healthy working life cycle1;2. Ageing is not simply an effect of time3‐5 but refers to many
changes in biological, psychosocial, and social functioning over time4‐7, and therefore has
an effect on the personal, organizational, and societal levels. De Lange et al.8 highlighted
this complex operationalization of ageing in the workplace, and they referred to the
approaches suggested by Sterns and Doverspike9 to conceptualize age. Five different
approaches to ageing were distinguished: chronological age, functional or performance
based age, psychosocial or subjective age, organizational age and the life span concept of
age to conceptualize ageing at work. The authors emphasized the need to pay attention to
these different types of ageing and their influence on work outcomes.
In this study we focused on chronological age and functional age and their
associations with work outcomes. Chronological age refers to one’s calendar age, which is
significantly associated with a decreased work ability10;11, and early discontinuation of
working life12‐14. Functional age refers to a worker’s performance and recognizes that
there is a variation in individual abilities and functioning through different ages7;8. In this
study we defined functional age by health status and the presence of a chronic health
condition. Chronic health condition typically begin in middle age6;15;16, and have an
adverse impact on the employability of workers17‐19. Previous studies investigated the
impact of functional age, measured with self‐related health, on the motivation to continue
to work of older workers. They found positive correlations between functional age and
motivation in older people (>60 years)7. Up to now, no studies are available which
investigate both the impact of chronological and functional age on work outcome.
Therefore, the aim of this study is to examine the relationships between ageing
and work outcomes. First, the relation between chronological and functional age was
determined. Secondly, the association between chronological age and five work outcomes
‐work ability, reported problems, barriers, facilitators and support needs due to ageing‐
was examined. Finally, the association between functional age and the five work
outcomes was examined. In addition, an overview of the most frequency reported
problems, barriers, facilitators and support needs due to ageing is outlined.
METHODS
General procedure and settings
The data of this cross‐sectional survey study were obtained from workers aged 45 years
and older. Nine companies in the northern part of the Netherlands, invited by their
occupational health physicians, were willing to participate in the study. These
Chapter 3
46
organizations represent four different sectors: health care, education, government and
industry.
A self‐administered questionnaire, consisting of 132 items on demographics,
questions about ageing, chronic diseases, health status and work ability, was sent to all
workers aged 45 years and older (N=8417). All companies enclosed a letter of
recommendation. The anonymity of respondents and confidentiality of the information
they provided were guaranteed. Four weeks after the initial mailing, all workers received a
written reminder. The data were collected in February and March 2008.
Ethical approval was sought from the Medical Ethics Committee of the University
Medical Center Groningen, which advised that, according to Dutch law, ethical clearance
was not required for this cross‐sectional study.
Measures
Age, gender and educational level were among the demographic characteristics. Three
items on occupation, sector and hours worked weekly were used to assess work
characteristics. Occupation was divided into four groups: executive, secretarial, policy; and
management. An open‐ended question was used to determine the number of hours
worked weekly under contract, and categorized in three groups: <25 hours; 25–40 hours;
and >40 hours.
Chronological age was based on the calendar age of the workers and was categorized in
five years age groups: 45‐49; 50‐54; 55‐59; 60‐64 years.
Functional age was measured with questions about perceived health status and
the presence of a chronic health condition. Health status was measured using the Dutch
version of the SF‐36 Health Survey20. The SF‐36 is a reliable and validated instrument that
consists of 8 scales covering: (i) physical functioning (10 items); (ii) role limitations
resulting from physical problems (4 items); (iii) social functioning (2 items); (iv) role
limitations resulting from emotional problems (3 items); (v) mental health (5 items); (vi)
vitality (4 items); (vii) pain (2 items); and (viii) general health (5 items). The scores of each
of the subscales range from 0 to 100, with higher scores reflecting a better health status20.
In accordance with many other studies, a chronic disease was defined as ‘the
subjective experience of long‐term irreversible disease of more than 3 months
duration’21;22. The presence of a chronic health condition was measured by asking the
respondents the following question: ‘Do you currently have a long‐term or chronic disease
of more than 3 months duration without the prospect of recovery?’ (yes/no). In addition,
the workers with a chronic health condition were asked if they experienced some degree
of hindrance due to the chronic health condition. If hindrance was reported, the worker
Chronological age, functional age and work outcomes
47
was asked to describe the degree of hindrance on a numeric scale of 0 (no hindrance) to
10 (a lot of hindrance).
Work outcomes were: work ability, problems while working due to ageing, barriers to
perform work due to ageing problems, facilitators in the work situation and support needs
to continue work. Work ability was measured by the Work Ability Index (WAI)23, a self‐
administered questionnaire comprising seven scales: (i) subjective estimation of current
work ability compared with lifetime best (0–100 points); (ii) subjective work ability in
relation to both physical and mental demands of the work (2–10 points); (iii) number of
diagnosed diseases (1–7 points); (iv) subjective estimation of work impairment due to
diseases (1–6 points); (v) sickness absenteeism during the past year (1–5 points); (vi) own
prognosis of work ability after 2 years (1 or 4 of 7 points); and (vii) psychological resources
(enjoyment of daily tasks, activity and life spirit, optimism about the future) (1–4 points).
The reliability24 and validity25 of the WAI are acceptable. Based on this WAI score, the
individual’s work ability was classified into two categories: moderate/poor (7–36 points),
and excellent/good (37–49 points)2;26.
Dichotomous (yes/no) questions were used for the other outcomes: problems,
barriers, facilitators and support needs. The first question assessed whether the workers
experienced ageing problems: ‘Do you encounter problems in working life due to ageing?’.
The next two questions concerned the barriers and facilitators to continuing working life:
‘Do you experience barriers in performing work tasks due to ageing problems?’ and ‘Are
there factors in your work which facilitate you in maintaining a sustainable working life?’.
The final question was about the support needs to continue working life in the coming
years: ‘Do you need support in the work situation to continue working life in the coming
years despite ageing?’. All respondents were asked to report a maximum of three
examples of problems, barriers, facilitators and support needs. For each question with a
‘yes’ answer, the workers were asked to describe the factors which were on top of their
mind.
Statistical analyses
A description of the sociodemographic characteristics was given by frequencies and
percentages. We used different types of analyses to examine the associations between
chronological and functional age and work outcome measures. Firstly, we examined the
association between the age‐groups (chronological age) and the five work outcome
measures by using logistic regression analyses. We adjusted for gender, education,
occupation, sector and working hours. To examine the association between functional age
Chapter 3
48
and the five work outcomes, univariate and multivariate analyses were conducted,
adjusting for chronological age, gender, education, occupation, sector and working hours.
All variables with a p‐value less than 0.20 in the univariate analyses were selected for the
multivariate analysis. To study the association between chronological age and functional
age, one‐way ANOVA test was used to compare differences between age‐groups on the
measures of functional age (health status and presence of chronic health condition).
Statistical significance was conducted for p<.05 in the logistic regression analyses, ANOVA
tests and the multivariate analysis. All analyses were carried out with the statistical
package SPSS version 16.0.
Chronological age, functional age and work outcomes
49
Table 1: Characteristics and work outcomes among workers aged 45 years and older (n=2971)
Variable n %
Age category (in years)
45‐49 856 29
50‐54 923 31
55‐59 847 28
60‐64 345 12
Female worker 1524 51
Chronic health condition 1100 37
Education
No education/ Primary School 53 2
Lower vocational education 447 16
Intermediate secondary and vocational education 673 23
Higher vocational education and university 1717 59
Sector
Health care 1207 41
Education 1261 42
Production 274 9
Government 229 8
Occupation
Executive 1782 61
Secretarial / Administrative 374 13
Policy 376 13
Management 395 13
Working hours
< 24 694 24
25‐40 2194 74
> 40 55 2
Work outcomes
Problems while working due to ageing (yes) 1236 42
Barriers to perform work due to ageing problems (yes) 735 25
Facilitators in the work situation (yes) 2419 82
Support needs to continue work (yes) 1138 38
Work ability score
Excellent/good 2213 75
Moderate/poor 751 25
Chapter 3
50
RESULTS
Characteristics sample
A total of 8417 workers aged 45 years and older from the nine included organizations
were invited to participate in the study, and 3008 returned the self‐administered
questionnaire (36% response). Because age is one of the main variables in our analyses,
we excluded 37 workers who did not report their age. The response rate differed across
the nine organizations (28‐55%), and seems to be associated with the number of
employees in the organizations. The response rate in the two largest organizations (more
than 4000 workers) was below 36%. All other organizations scored around 36% or higher.
The mean age of the workers was 53.4 years (SD 5.0) ranging from 45‐64 years of age.
Most workers were highly educated (59%) and most of them were working in the sectors
education (42%) and health care (41%). The presence of a chronic health condition was
reported by 37% of the workers. Most frequently reported chronic health conditions were
musculoskeletal diseases (n=878, 25%), followed by mental health conditions (n=390,
11%), neurological or sensory disease (n=351, 10%), and cardiovascular diseases (n=99,
9%). Of those workers who reported the presence of a chronic health condition, 50%
reported some degree of hindrance due to the chronic health condition. The degree of
hindrance due to the chronic disease, expressed on a numeric scale of 0 (no hindrance) to
10 (a lot of hindrance), was on average 6.7 (SD 2.4). With regard to the work outcome
measures, the work ability of 75% (n=2213) of the workers was excellent/good. In total
42% (n=1236) workers reported problems while working due to ageing, 25% (n=735)
experienced barriers in performing work tasks, 82% (n=2419) reported facilitators and
38% (n=1138) of the workers reported support needs to continue work in the next coming
years. Detailed information about these characteristics are presented in Table 1.
The association between chronological age and functional age
Chronological age was not significantly associated with the presence of a chronic health
condition (p=0.34). All other outcome measures of functional age differ significantly
between the age groups (p<.05) (Table 2). Post‐hoc analyses indicated that the youngest
workers (45‐49 year) scored significantly higher on physical functioning compared to the
other groups (p<.02), and the general health of these workers was significant better than
workers aged 55‐59 years (p<.04). The workers in the oldest age group (60‐64 years)
reported significantly higher scores on the subscales social functioning (p<.05), mental
health (p<.05) and vitality (p<.001) compared to the other age‐groups.
51
Table 2: Influen
ce of chronological age, based
on 5‐years age groups, on functional age
Chronological age
(years)
Fp
Functional age
Total
(n=2971)
45‐49
(n=856)
50‐54
(n=923)
55‐59
(n=847)
60‐64
(n=345)
Mean
scores
Physical functioning
90.38
91.84
89.68
88.35
88.98
8.407
<.001*
Social functioning
83.94
83.87
82.83
83.42
88.38
6.465
<.001*
Men
tal health
69.85
69.78
69.03
69.84
72.26
5.895
0.001*
Vitality
62.80
62.09
61.90
62.92
66.73
10.733
<.001*
Gen
eral health
69.74
71.12
69.03
68.76
70.63
3.37
0.018*
Frequency
Presence chronic health condition (%)
1113 (37%)
292 (34%)
347 (38%)
334 (39%)
117 (34%)
0.341
*p<.05
52
Table 3: A
ssociation between chronological age and problems, barriers, facilitators, support needs and work ability, adjusted
for
gender, education, occupation, sector and working hours
Age
groups
(years)
Problems while
working due to ageing
(reference=n
o)
Barriers to perform
work due to ageing
(reference=n
o)
Facilitators in
the work
situation
(reference=n
o)
Support need
s to
continue work
(reference=n
o)
Excellent or good work
ability (reference=
moderate/ poor)
OR
95% CI
OR
95% CI
OR
95% CI
OR
95% CI
OR
95% CI
45‐49
(referen
ce)
1.00
1.00
1.00
1.00
1.00
50‐54
1.343*
1.101‐1.638
0.982
0.742‐1.396
0.732*
0.555‐0.965
1.301*
1.065‐1.590
0.683*
0.538‐0.867
55‐59
1.641*
1.337‐2.013
0.964
0.754‐1.427
0.583*
0.442‐0.768
1.389*
1.130‐1.709
0.529*
0.416‐0.673
60‐64
1.177
0.893‐1.551
0.801
0.805‐1.938
0.585*
0.412‐0.831
0.928
0.697‐1.235
0.661*
0.481‐0.908
* p<0.05
OR = odds ratio, CI =
confiden
ce interval
Chronological age, functional age and work outcomes
53
Chronological age and work outcome measures
In table 3 the results of the association between chronological age and experienced
problems, barriers, facilitators, support needs and work ability are presented. Workers in
the age‐groups 50‐54 years (OR 1.34; 95% CI 1.10‐1.64) and 55‐59 years (OR 1.64; 95% CI
1.34‐2.01) reported significant more problems while working due to ageing compared to
workers aged 45‐49 years, but also reported more support needs to continue working life
in the next coming years (respectively OR 1.30; 95% CI 1.07‐1.59 and OR 1.39; 95% CI 1.13‐
1.71). Workers between 50‐64 years of age experienced significantly less facilitators in the
work situation compared to the youngest age group (OR between 0.58‐0.73). Workers
above 50 years of age had significant more chance on a moderate/poor work ability (OR
between 0.53 and 0.68). However, the chance of moderate/poor work ability was
significantly lower in the oldest age group compared to the workers between 55‐59 years
of age. No significant differences between age‐groups were found for barriers to perform
work.
Functional age and work outcome measures
Table 4 gives the crude and multivariate odds ratios and 95% confidence intervals on
measures of functional age on work outcomes. Univariate logistic regression analyses
showed that the measures of functional age (health status subscales and presence of
chronic health condition) were significantly associated with all work outcome measures
(p<.20), except for the association between the presence of a chronic health condition and
experienced facilitators (p=0.44). In the multivariate analyses most health status subscales
(except mental health) and the presence of a chronic health condition remained
statistically significant. Higher scores on vitality were associated with less problems due to
ageing (OR 0.98; 95%CI 0.97‐0.98), less barriers to perform work (OR 0.97; 95%CI 0.96‐
0.99), more perception of facilitators (OR 1.02; 95%CI 1.00‐1.03), less support needs to
continue working life (OR 0.97; 95%CI 0.96‐0.98) and more chance of excellent/good work
ability (OR 1.04; 95%CI 1.02‐1.05). Having a chronic health condition resulted in more
chance to report problems due to ageing (OR 1.52; 95% CI 1.26‐1.83), barriers to perform
work (OR 2.01; 95% CI 1.51‐2.68), more chance to report experienced support needs to
continue working life (OR 1.52; 95% CI 1.26‐1.84) and less chance to score moderate/poor
work ability (OR 0.35; 95% CI 0.27‐0.45). Mental health did not remain significantly in the
final multivariate model for all work outcome measures.
Chapter 3
54
Table 4: Association between functional age and problems, barriers, perceptions, support
needs, and work ability adjusted for chronological age, gender, education, occupation,
sector and working hours.
Univariate Multivariate
OR 95%CI p OR 95%CI p
Problems while working due to ageing (reference=no)
Physical functioning1 0.973 0.967‐0.978 <.001* 0.993 0.986‐1.000 0.048**
Social functioning1 0.977 0.973‐0.981 <.001* 0.999 0.993‐1.004 0.664
Mental health1 0.962 0.956‐0.969 <.001* 0.991 0.981‐1.000 0.060
Vitality1 0.957 0.951‐0.962 <.001* 0.975 0.966‐0.984 <.001**
General health1 0.970 0.965‐0.975 <.001* 0.991 0.985‐0.997 0.002**
Chronic health condition 2.450 2.088‐2.875 <.001* 1.518 1.261‐1.828 <.001**
Barriers to perform work due to ageing (reference=no)
Physical functioning1 0.948 0.937‐0.959 <.001* 0.976 0.964‐0.988 <.001**
Social functioning1 0.963 0.956‐0.970 <.001* 0.983 0.974‐0.992 <.001**
Mental health1 0.964 0.955‐0.974 <.001* 1.004 0.989‐1.020 0.574
Vitality1 0.946 0.937‐0.956 <.001* 0.973 0.958‐0.987 <.001**
General health1 0.964 0.956‐0.971 <.001* 0.997 0.987‐1.008 0.600
Chronic health condition 3.571 2.780‐4.587 <.001* 2.012 1.508‐2.684 <.001**
Facilitators in the work situation (reference=no)
Physical functioning1 1.005 0.999‐1.012 0.123* 0.996 0.988‐1.004 0.301
Social functioning1 1.011 1.007‐1.016 <.001* 1.005 0.998‐1.012 0.158
Mental health1 1.018 1.010‐1.025 <.001* 1.001 0.990‐1.013 0.846
Vitality1 1.020 1.013‐1.027 <.001* 1.015 1.004‐1.026 0.008**
General health1 1.010 1.004‐1.016 0.001* 1.001 0.994‐1.009 0.747
Chronic health condition 0.922 0.750‐1.134 0.443 ‐‐‐‐ ‐‐‐‐ ‐‐‐‐
Support needs to continue work (reference=no)
Physical functioning1 0.979 0.973‐0.984 <.001* 1.001 0.944‐1.008 0.819
Social functioning1 0.974 0.970‐0.978 <.001* 0.993 0.987‐0.998 0.012**
Mental health1 0.962 0.956‐0.969 <.001* 0.996 0.987‐1.006 0.454
Vitality1 0.955 0.949‐0.961 <.001* 0.970 0.962‐0.979 <.001**
General health1 0.973 0.968‐0.978 <.001* 0.995 0.989‐1.001 0.091
Chronic health condition 2.380 2.025‐2.798 <.001* 1.523 1.261‐1.838 <.001**
Chronological age, functional age and work outcomes
55
Table 4 continued Univariate Multivariate
OR 95%CI p OR 95%CI p
Excellent or good work ability (reference= moderate/poor)
Physical functioning1 1.078 1.069‐1.087 <.001* 1.030 1.021‐1.039 <.001**
Social functioning1 1.066 1.060‐1.072 <.001* 1.030 1.022‐1.038 <.001**
Mental health1 1.072 1.064‐1.081 <.001* 1.004 0.991‐1.017 0.572
Vitality1 1.100 1.090‐1.109 <.001* 1.034 1.020‐1.047 <.001**
General health1 1.090 1.083‐1.100 <.001* 1.047 1.038‐1.057 <.001**
Chronic health condition 0.122 0.100‐0.149 <.001* 0.351 0.271‐0.451 <.001** 1Higher scores on the scale means a better physical functioning, social functioning, mental health, vitality or general health * p<.20 **p<.05 OR = odds ratio, CI = confidence interval
Overview of the problems, barriers, facilitators and support needs
In the group of workers (42%; n=1236) who reported problems while working due to
ageing, the most frequently reported problems were energy decline (fatigue) (17%),
muscle function decline (strength and endurance) (11%), concentration lapses (10%), and
memory deterioration (8%). Most experienced barriers to perform work tasks, reported by
25% of the workers (n=735), were tasks which require concentration (22%), lifting and
carrying objects (11%), and work pace (9%). Most reported facilitators, by 82% (n=2419) of
the workers, were support from colleagues (19%), formal relations in work (e.g. clients,
patients or students) (12%) and the supervisor (8%). The workers reported predominantly
support needs (38%, n=1138) with regard to services, systems and policies at the company
level (53%), for example adjustments in tasks and functions, individual agreements about
working hours and days, and variety and autonomy.
Chapter 3
56
DISCUSSION
The results of this study showed that chronological age and functional age are related,
although the presence of a chronic health condition was not influenced by age. Workers
with higher chronological age, especially between 50 and 59 years, experienced more
problems due to ageing, fewer facilitators to continue working life and reported
frequently more support needs to continue work in the next coming years compared to
the younger ones. In addition, the work ability scores decreased by age. Experienced
barriers to perform work were not associated with chronological age. The results of this
study may suggest that employers can do far more to help older workers to remain in the
workplace towards a sustainable healthy working life.
Workers in the oldest age group (60‐64) reported higher scores on social functioning,
mental health and vitality compared to the youngest age group (45‐49). Although the
general health of workers aged 55‐59 years was significantly lower than the mean scores
of the workers in the youngest age group, no significant difference was found for workers
in the oldest age group. Also no significant difference was found for the presence of a
chronic health condition between the two age groups. Based on the literature, it was
expected that older workers had lower scores on measures of health status6 and those
workers experienced frequently more chronic health conditions15;16. This finding might be
explained by the healthy worker effect, a phenomenon which is often studied in
occupational cohorts27;28. Workers, especially the older workers, usually exhibit better
health conditions than the general population because severely ill and chronically disabled
are ordinary excluded from employment. This healthy worker effect might also explain
why we found no significant difference between the oldest and youngest age group in the
association between chronological age and work outcomes. The workers between 60 and
64 who are still working, might be a very select, relatively healthy group of the general
population of this age. Because of this selection bias due to the healthy worker effect, the
results in this report are probably an underestimation of the problems in the entire age
group.
Functional age was significant associated with work outcomes; the associations
were significant, but small odds ratios were found, except for the presence of a chronic
health condition. Mental health did not contribute to experienced problems, barriers,
facilitators, support needs, and work ability. The impact of the presence of a chronic
health condition was reduced by the other measures of functional age. Due to ageing, 42%
of the workers aged 45 years and older reported problems in the work participation, and
37% reported a chronic health condition. Although most workers (82%) experienced
facilitators in the work situation, 25% of the workers experienced barriers to perform
Chronological age, functional age and work outcomes
57
work as well. To continue work in the next coming years 38% of the workers experienced
support needs.
A strength of the study is that it was based on a considerable sample size of
workers with various occupational activities (e.g. heavy physical labour, back office, health
care, teaching and cleaning), employed in different companies. While this study had the
advantage of using a population‐based sample, there are some limitations in generalizing
these findings.
The overall response rate of 36% at baseline was regarded to be reasonable for an
anonymous survey in the working population, but results related to selective participation
cannot be ruled out. Because of the anonymous study design, we were not able to
investigate the characteristics of the non‐responders properly. Nevertheless, we believe
there is no reason to expect that workers with problems due to functional age or a chronic
health condition returned the questionnaire less frequently than workers without
problems. The questionnaire addressed a variety of themes, and did not emphasize
functional age or chronic health condition.
A second issue concerns the self‐reporting nature of the study because the perception of
workers’ responses could not be externally validated. As a result, some bias may exist in
the classification of respondents on the basis of self‐reported data, resulting in an
underestimation of the differences and associations under study. However, it is known
from literature that the self‐reporting of health status and of certain physical chronic
diseases (diabetes, cardiovascular disease, musculoskeletal and respiratory problems) is
reasonably reliable29. Therefore, we do not expect that the self‐reporting of health and
problems due to ageing introduced any significant bias for this kind of health conditions.
However, this expectation is based on a limited number of studies concerning physical
conditions and might not self‐evidently be generalizable to other physical or mental health
conditions.
Finally, the current study does not distinguish between specific chronic health
conditions because of the lack of knowledge of the severity and limitations of the
conditions. Not distinguishing between workers suffering from various chronic health
conditions in relation to a sustainable working life is supported by Detaille et al. among
physically ill workers30;31. They showed that different groups of chronically ill workers
were experiencing the same bottlenecks, although their priority varied. These findings
support the idea that the impact of chronic health conditions may be applicable for
workers in general, in the Netherlands and other industrialized countries.
An overview was given of the most frequency reported problems, barriers,
facilitators and support needs due to ageing. We used the responses based on open‐
Chapter 3
58
ended survey items and calculated for each work outcome separately which example of
problems, barriers, facilitators and support needs were reported most frequently in our
sample. We found that factors to enhance working life were reported at both personal
and organizational level. The next step for research is to outline in more detail analysis on
subgroup level (e.g. differences between age groups or workers who report problems
while working due to ageing) on the most frequently experienced barriers to perform
work, facilitators in the work situation and support needs to continue working life. Based
on qualitative analyses, a list of relevant factors can be developed. Insight in these factors
may be useful for developing interventions and strategies towards a sustainable healthy
working life.
KEY POINTS
Due to ageing, 42% of the workers aged 45 years and older reported problems
while working, 37% reported a chronic health condition.
The presence of a chronic health condition was not influenced by chronological
age in workers aged 45 years and older.
Increased chronological age resulted in more experienced problems, more
support needs, less experienced facilitators and decreased work ability.
With respect to functional age, predominantly a chronic health condition was
associated with more problems, more barriers, more support needs and lower
work ability scores.
Reported problems in work functioning increased with chronological age, but
workers in the aged group 60‐64 years did not report more problems and barriers
compared to workers between 45‐49 years of age.
Chronological age, functional age and work outcomes
59
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4
Chronic health conditions and work ability in the ageing
workforce: the impact of work conditions, psychosocial factors
and perceived health
Accepted Int Arch Occup Environ Health. 2013 [Epub ahead of print]
W. Koolhaas
J.J. van der Klink
M.R. de Boer
J.W. Groothoff
S. Brouwer
Chapter 4
62
ABSTRACT
Purpose: The aim of this study was to determine the influence of work conditions,
psychosocial factors and perceived health on the association between the presence of a
chronic health condition and (single item) work ability among workers aged 45 years and
older. In addition, we aimed to examine variables associated with work ability for workers
with and without a chronic health condition separately.
Methods: The data of this cross‐sectional study were obtained from 5247 workers aged
45 years and older in five different work sectors. Work ability was assessed with the first
item of the Work Ability Index. The presence of a chronic health condition was assessed by
self‐report. Independent variables in the multivariable linear regression analysis were
work conditions, psychosocial factors and perceived health status.
Results: The presence of a chronic health condition was negatively associated with work
ability (B = ‐0.848). The strength of this association slightly attenuated after subsequently
adding individual characteristics (B = ‐0.824), work conditions (B = ‐0.805) and more so
after adding psychosocial factors (B = ‐0.704) and especially perceived health variables
(B = ‐0.049) to the model. Variables associated with work ability for workers with and
without a chronic health condition were similar.
Conclusion: Perceived health and psychosocial factors, rather than work conditions,
explained the association between the presence of a chronic health condition and work
ability. Substantial differences of variables associated with work ability for workers with
and without a chronic health condition were not found. Based on the lower mean scores
for workers with a chronic health condition for work ability as well for predictors, these
workers might have the most benefit by a policy focussing on enhancing these associated
variables.
Key words: Ageing workers, Chronic health condition, Perceived health, Psychosocial
factors, Work ability, Work conditions
Chronic health conditions and work ability
63
INTRODUCTION
There is ample evidence of the burden of chronic conditions on health and work
outcomes1‐4. Given the fact that the prevalence of chronic conditions increases with age
and that person will be required to work until higher ages, the prevalence of chronic
conditions in the working population can be expected to increase even further5,6. This
might hamper the contribution of large parts of the working age population to the work
process, especially for workers aged 45 years and older. A recent study showed that in the
Dutch working population of 45 years of older one in three workers indicated a chronic
health condition7. Chronic health conditions have an adverse impact on the employability
of workers8‐10. Previous research about differences between workers with and without a
chronic health condition shows that workers with a chronic health condition experiences
more problems due to ageing, more barriers to perform work, more support needs and
lower work ability scores7. For sustainable employability it is crucial that work demands
are adjusted to the health status and abilities of the individual worker.
Within this framework, the concept of work ability has been developed as an
important multi‐factorial concept that can be used to identify workers at risk for an
imbalance between health, personal resources and work demands11,12. The work ability
concept is based on the assumption that work ability is determined by an individual’s
perception of the demands at work and the ability to cope with them. Previous research
showed that work ability, measured with the Work Ability Index (WAI), is negatively
influenced by older age, high physical work demands, high psychosocial work demands,
unhealthy lifestyle and a poor physical fitness12‐16. It is also known from literature that it is
crucial to promote social support and networks at the workplace and in private life, as well
as a coping‐oriented approach to health issues and social life in order to strengthen work
ability among female employees in elderly care17. Furthermore, lower work ability levels
have been shown to result in decreased work performance, productivity loss, long‐term
sickness absence and early exit from work7,10,13,18‐21. In addition, several studies have
established a strong association between perceived health status and work ability18,22‐26.
Although previous studies confirmed the associations between psychosocial,
work‐related factors and perceived health on work ability in different occupational
populations and age groups, to our knowledge, none of these studies so far have studied
the impact of these potential explanatory factors on the association between the
presence of a chronic health condition and work ability. One of the underlying reasons
might be that the WAI is an instrument that contains many disparate questions more or
less indirectly measuring work ability (eg. relating to diagnosis of chronic conditions and
sick leave). This may have implications when the WAI is used among workers already on
Chapter 4
64
sick leave; also, it may give too much weight to diagnoses not necessarily related to work
ability18. As a result, the single‐item question on work ability has often replaced the WAI in
clinical and occupational practice18,27,28. Ahlstrom found strong associations between the
WAI and the single‐item question with sick leave, health and symptoms among long‐term
sick‐listed women working in human service organizations. Moreover, they found strong
predictive value for the degree of sick leave and health‐related quality of life for the
single‐item question. Although further validation studies are still lacking the single‐item
question on work ability may be a good alternative to the WAI. The benefits for using the
single‐item question in our study is that it could be used as an indicator for assessing the
status of work ability among workers with and without a chronic health condition without
given too much weight to diagnoses not necessarily related to work ability when using the
WAI.
The main purpose of this study is to determine the impact of work conditions,
psychosocial factors, and perceived health on the association between the presence of a
chronic health condition and work ability among workers aged 45 years and older. In
addition, variables associated with work ability level will be examined for workers with
and without a chronic health condition separately.
METHODS
Design and study population
The data of this cross‐sectional survey study were obtained from workers aged 45 years
and older who worked in ten different organisations in the Netherlands. These
organisations represent five different sectors: health care, education, government,
production industry and telecommunication. A self‐administered questionnaire was sent
to all participants (n=13897). All companies enclosed a letter of recommendation. The
anonymity of respondents and confidentiality of the information they provided were
guaranteed. Four weeks after the initial mailing, all workers received a written reminder.
Information from questionnaires was available from 5730 workers. The overall response
was 40% varying from 28% (health care) to 58% (production) across organisations. 483
workers (8%) were excluded from the analyses because of incomplete data. These workers
with missing values had significant lower mean scores on years paid work (‐1.35 years)
and active coping (‐0.60 points) and consisted of a significantly higher percentages of
women (42% vs 33%), lower educated workers (29% vs 22%), executive workers (56% vs
46%), production workers (18% vs 4%), workers with physical work (15% vs 6%) and
lower percentages of workers with mental work (55% vs 65%) or working in the sector
telecommunication (31% vs 49%) than those workers included in the study.
Chronic health conditions and work ability
65
Ethical approval was sought from the Medical Ethics Committee of the University Medical
Center Groningen, which advised that, according to Dutch law, ethical clearance was not
required for this cross‐sectional study.
Work ability
Self‐reported work ability was measured by the first item of the work ability index:
“current work ability compared with the lifetime best”. The value 0 represents ‘completely
unable to work’ and 10 the ‘work ability at its best’29. Previous research has established
that the single‐item question on work ability can be used as a reliable indicator for
assessing the status and progress of work ability16,18,21,28.
Chronic health condition
We defined a chronic disease as ‘the subjective experience of a long‐term irreversible
disease of more than 3 months duration’ which is in accordance with many other
studies7,30,31. It was assessed by asking the respondents the following question: ‘Do you
currently have a long‐term or chronic disease of more than 3 months duration without the
prospect of recovery?’ (yes/no).
Individual characteristics
Data of age, gender and education were collected by questionnaire. Age was based on the
calendar age of the workers. The highest education level successfully completed was
categorized into low (no education, primary or secondary education) and high (post‐
secondary education).
Work conditions
Organisations were categorized in the sectors health care, education, government,
telecommunication and production. Participants were asked in which of the following
occupational areas they worked: executive, secretarial, policy, or management. The
duration of the current function and years of paid work were reported in years. A
dichotomous (yes/no) question was used to assess shift work. Self‐reported work type
assessed with a single questions, based on the question in the WAI, was used to classify
workers into physical, mental or both.
Psychosocial factors
Perceived work attitude was measured with the Dutch language version of the Work
Involvement Scale (WIS‐DLV), reflecting the degree to which a person wants to be
Chapter 4
66
engaged in work32. The questionnaire consists of six items with responses on a 1‐4 point
scale (strongly disagree, disagree, agree, and strongly agree). Higher scores on the WIS‐
DVL indicate a more positive attitude towards work. The internal consistency (Cronbach’s
alpha) of the WIS‐DLV in this study was 0.72.
The Utrecht Coping List (UCL) was used to assess styles of coping33. This
questionnaire was designed to measure the coping strategies people use in stressful
situations. In this study we used the short version of the original 47‐item Utrecht Coping
List (UCL, 1995) which include a selected number of dimensions and items and consisting
of three scales: (1) active problem‐focusing (five items), (2) expression of emotions (four
items), and (3) avoidance behaviour (four items). We used the active and passive coping
styles in this study which were shown to be important constructs in other work and health
related studies34‐36. The internal consistencies as well as the test‐retest reliabilities have
been shown to be satisfactory33. The internal consistencies found for active, expression of
emotions and avoiding focused coping strategies in this study were 0.84, 0.70, and 0.71
respectively.
Perceived support was measured with a self‐constructed scale reflecting a
person’s perception of social support. The 14 items were answered on a 5‐point Likert
scale (totally disagree to totally agree). A confirmatory factor analysis was carried out in
three subscales: 1) co‐workers support (two items), 2) community support (six items), and
3) organisational support (six items). Higher scores indicate more support for all scales.
The internal consistencies for co‐workers, community, and organisational support in this
study were, 0.66, 0.70, and 0.72 respectively.
Health status
Perceived health status was assessed with the Dutch version of the SF‐36 Health Survey
consisting of eight multi‐item scales: physical functioning, role limitations due to physical
health problems, pain, general health perceptions, vitality, social functioning, role
limitations due to emotional problems, and mental health37. Higher scores indicate higher
levels of functioning and health (range 0–100). The internal consistency of the subscales
was between the 0.74 (subscale general health) and 0.89 (subscales role limitations for
physical problems and role limitations for emotional problems).
Statistical analyses
Multivariable linear regression analysis were performed to examine the impact of the
potential explanatory factors (i.e. work conditions, psychosocial factors, and perceived
health status) on the association between the presence of a chronic health condition and
Chronic health conditions and work ability
67
work ability. To estimate to what extent this association could be explained by the
predictors, multiple linear regressions were performed using a forward stepwise method.
In this method, predictors were entered (forwards) in blocks. In model 1 chronic health
condition was entered. The individual characteristics were entered in model 2, followed by
the work conditions in model 3, the psychosocial factors in model 4 and the perceived
health status variables in model 5. To determine the impact of the work conditions,
psychosocial factors and perceived health on the association between the presence of a
chronic health condition and work ability, we included all variables which were
significantly associated in the stepwise analyses of model 1 to 5 in all models.
Subsequently, we separately added the potential variables to the multivariate model
which were not statistically significant in the univariate analysis to determine their
association with the outcome measure in the presence of other prognostic factors.
To determine variables associated with work ability for workers with and without a
chronic health condition, analyses were stratified by the presence of a chronic health
condition. All significant variables in the multivariable model for one of the groups were
included in the models for other groups as well in order to provide an appropriate
comparison. The level of significance for all statistical tests was set at an alpha of 0.05 (2‐
sided) using the Statistical Package for the Social Sciences (SPSS, Inc, Chicago, IL, USA),
version 16.0.
RESULTS
The study population included 3508 men (67%) and 1734 women (33%) of the five
different sectors; production (4%), education (23%), health care (20%), government (4%)
and telecommunication (49%). The mean age of the workers was 53.0 years (SD 4.4)
ranging from 45 to 64 years of age. The majority (77%) of the workers was highly
educated. The mean score on work ability was 8.1 (SD 1.4, median 8.0) ranging from 0 to
10. Detailed information about these characteristics is presented in Table 1. Thirty‐five per
cent of the workers had a chronic health condition, with the highest prevalence for
musculoskeletal conditions (n=1497, 81%), neurological or sensory disease (n=654, 35%),
and cardiovascular diseases (n=634, 34%) (data not shown).
68
Table 1: B
aseline characteristics of the study population with subgroup analyses for workers with and without a chronic health
condition
Characteristics
Total population
(n = 5247)
Without a chronic health
condition (n = 3395)
With a chronic health
condition (n = 1852)
N
Mean
(SD
) (%
) N
Mean
(SD
) (%
) N
Mean
(SD
) (%
)
Age (yr)
53.0 (4.4)
52.9 (4.5)
53.3 (4.3)
Gender
Male
3508
67
2348
69
1160
63
Fem
ale
1739
33
1047
31
692
37
Education
Low
1181
23
692
20
489
26
High
4066
77
2703
80
1363
74
Chronic health condition (yes)
1852
35
1852
100
Work conditions
Occupation
Executive
2429
46
1512
45
917
50
Secretarial
1063
20
658
19
405
22
Policy
1009
20
695
20
314
17
Managem
ent
746
14
530
16
216
11
Sector
Production
192
4118
374
4
Education
1170
23
743
22
427
23
Health care
1099
20
676
20
423
23
Governmen
t212
4143
469
4
Telecommunication
2574
49
1715
51
859
46
69
Table 1: continued
Characteristics
Total population
(n = 5247)
Without a chronic health
condition (n = 3395)
With a chronic health
condition (n = 1852)
N
Mean
(SD
) (%
)N
Mean
(SD
)(%
)N
Mean
(SD
)(%
)
Curren
t function (years)
21.6 (11.6)
21.3 (11.6)
22.1 (11.6)
Paid work (years)
31.9 (7.0)
31.6 (6.9)
32.4 (7.0)
Work type
Men
tal
3446
66
2322
68
1124
61
Physical
311
6180
6131
7
Both m
ental and physical
1490
28
893
26
547
32
Shift work (yes)
586
11
368
11
218
12
Psychosocial factors
Work attitude
66.1 (19.8)
67.5 (19.1)
63.4 (20.9)
Coping
Active problem focusing
14.8 (2.6)
14.8 (2.6)
14.7 (2.6)
Expression of em
otions
8.4 (1.9)
8.4 (1.8)
8.6 (2.0)
Avoidance beh
aviour
8.2 (2.0)
8.1 (2.0)
8.3 (2.0)
Support
Co‐w
orkers
4.2 (2.0)
4.1 (2.0)
4.4 (2.0)
Community
24.0 (4.7)
24.4 (4.5)
23.4 (4.8)
Organisational
19.5 (4.0)
19.6 (3.9)
19.4 (4.3)
Perceived health status
Physical functioning
90.2 (14.2)
94.3 (9.6)
82.7 (17.7)
Social functioning
84.8 (19.8)
89.8 (15.5)
75.7 (23.2)
Role limitations from physical
problems
77.2 (36.3)
86.2 (28.9)
60.7 (42.1)
70
Table 1: continued
Characteristics
Total population
(n = 5247)
Without a chronic health
condition (n = 3395)
With a chronic health
condition (n = 1852)
N
Mean
(SD
) (%
)N
Mean
(SD
)(%
)N
Mean
(SD
) (%
)
Role limitations from emotional problems
81.5 (35.2)
86.4 (30.7)
72.6 (40.7)
Men
tal health
70.1 (12.3)
72.1 (10.7)
66.4 (13.9)
Vitality
63.3 (14.2)
66.6 (12.6)
57.2 (15.0)
Pain
84.5 (19.2)
91.1 (14.4)
72.5 (21.0)
Gen
eral health
69.8 (17.3)
75.2 (14.0)
59.9 (18.4)
Work ability
Work ability score single item
8.1 (1.4)
8.4 (1.2)
7.5 (1.6)
Chronic health conditions and work ability
71
Table 2 shows that the presence of a chronic health condition was negatively associated
with work ability (B = ‐0.848). The effect of the individual characteristics and work
conditions on this association was small (B = ‐0.805), but the regression coefficient
attenuated to ‐0.704 after addition of the psychosocial factors. The presence of a chronic
health condition explained 8.2% of the variance in work ability. The proportion explained
variance increased after addition of the individual and work conditions with respectively
1.8% and 1.4%. The R‐square change after addition of the psychosocial factors in model 4
was 8.5% resulting in a total explained variance of 19.7% in work ability.
After adding the perceived health variables, the association between the presence of a
chronic health condition and work ability was strongly attenuated (B = ‐0.049) and ceased
to be statistically significant. The total explained variance of work ability of this final model
was 40.1%.
Analyses stratified by the presence of a chronic health condition are shown in Table 3. For
both workers with and without a chronic health condition psychosocial factors and
perceived health status were associated with work ability. Small, but significant
associations with very low B‐values, were found for workers suffering from a chronic
health condition for occupation and work type, whereas gender and age were significant
individual factors for workers without a chronic health condition. 42.8% of the variance in
work ability for workers suffering from a chronic health condition was explained by the
factors in the model, while these factors explained 28.7% of the variance for workers
without a chronic health condition.
72
Table 2: M
ultivariabele association of the presence of a chronic health condition, w
ork conditions, psychsocial factors
and perceived
health on work ability
Model 1
Model 2
Ba
Beta
b
95% CI for B
Ba
Beta
b95% CI for B
Lower
bound
Upper
bound
Lower
bound
Upper
bound
Presence of a chronic health condition
Chronic health condition (reference = no)
‐0.848 ¥
‐0.287
‐0.924
‐0.771
‐0.824 ¥
‐0.279
‐0.900
‐0.748
Individual characteristics
Age (yr)
‐0.027 ¥
‐0.084
‐0.035
‐0.018
Gender (referen
ce = m
ale)
0.063
0.021
‐0.014
0.140
Education (reference = low)
0.324 ¥
0.096
0.236
0.411
Work conditions
Occupation: secretary vs executive
Occupation: p
olicy vs executive
Occupation: m
anagem
ent vs executive
work type: physical vs. m
ental job dem
ands
work type: both physical and m
ental vs
men
tal job dem
ands
Total R
‐square (%)
8.2
10
R‐square change (%)
8.2
1.8
n
5247
5247
*p<.05; §p<.01; ¥p<.001, a
B, unstandardized
regression coefficient, b beta, standardized
regression coefficient
73
Table 2:continued
Model 3
Model 4
Ba
Beta
b
95% CI for B
Ba
Beta
b95% CI for B
Lower
bound
Upper
bound
Lower
bound
Upper
bound
Presence of a chronic health condition
Chronic health condition (reference = no)
‐0.805 ¥
‐0.273
‐0.880
‐0.729
‐0.704 ¥
‐0.239
‐0.777
‐0.632
Individual characteristics
Age (yr)
‐0.025 ¥
‐0.079
‐0.033
‐0.017
0.002
0.008
‐0.006
0.011
Gender (referen
ce = m
ale)
0.124 §
0.041
0.044
0.204
0.064
0.021
‐0.013
0.141
Education (reference = low)
0.230 ¥
0.068
0.139
0.322
0.130 §
0.038
0.041
0.218
Work conditions
Occupation: secretary vs executive
0.048
0.014
‐0.055
0.150
0.146 §
0.042
0.048
0.245
Occupation: p
olicy vs executive
0.147 §
0.041
0.042
0.253
0.115 *
0.032
0.014
0.216
Occupation: m
anagem
ent vs executive
0.351 ¥
0.087
0.236
0.465
0.195 ¥
0.048
0.084
0.306
Work type: physical vs. m
ental job dem
ands
‐0.419 ¥
‐0.070
‐0.585
‐0.254
‐0.293 ¥
‐0.049
‐0.453
‐0.134
Work type: both phy./m
en.vs men.Jobdem.
‐0.066
‐0.021
‐0.155
0.023
‐0.011
‐0.003
‐0.095
0.074
Psychosocial factors
Work attitude
0.007 ¥
0.105
0.005
0.009
Coping: active problem focusing
0.076 ¥
0.139
0.062
0.090
Coping: avoidance beh
aviour
‐0.068 ¥
‐0.097
‐0.085
‐0.051
Co‐w
orker support
‐0.053 ¥
‐0.075
‐0.070
‐0.035
Community support
0.055 ¥
0.182
0.046
0.064
Organisational support
‐0.006
‐0.017
‐0.015
0.003
Total R
‐square (%)
11.3
19.7
R‐square change (%)
1.4
8.5
n
5247
5247
Chapter 4
74
Table 2: continued
Model 5
Ba Betab 95% CI for B
Lower
bound
Upper
bound
Presence of a chronic health condition
Chronic health condition (reference = no) ‐0.049 ‐0.017 ‐0.122 0.024
Individual characteristics
Age (yr) ‐0.012 § ‐0.038 ‐0.02 ‐0.005
Gender (reference = male) 0.087 * 0.029 0.020 0.155
Education (reference = low) 0.092 * 0.027 0.016 0.169
Work conditions
Occupation: secretary vs executive 0.080 0.023 ‐0.006 0.165
Occupation: policy vs executive 0.021 0.006 ‐0.067 0.109
Occupation: management vs executive 0.084 0.021 ‐0.013 0.180
Work type: physical vs. mental job demands ‐0.195 § ‐0.033 ‐0.334 ‐0.057
Work type: both phy./men. vs men. Job dem. s 0.024 0.008 ‐0.050 0.097
Psychosocial factors
Work attitude 0.005 ¥ 0.075 0.004 0.007
Coping: active problem focusing 0.038 ¥ 0.069 0.025 0.050
Coping: avoidance behaviour ‐0.028 ¥ ‐0.041 ‐0.044 ‐0.013
Co‐worker support ‐0.008 ‐0.011 ‐0.023 0.007
Community support 0.028 ¥ 0.092 0.020 0.036
Organisational support ‐0.008 * ‐0.024 ‐0.016 ‐0.001
Perceived health status
Physical functioning 0.008 ¥ 0.082 0.005 0.011
Social functioning 0.007 ¥ 0.102 0.005 0.010
Role limitations from physical problems 0.004 ¥ 0.104 0.003 0.005
Role limitations from emotional problems 0.002 ¥ 0.055 0.001 0.003
Mental health 0.005 § 0.048 0.002 0.009
Vitality 0.017 ¥ 0.176 0.014 0.021
Pain 0.003 * 0.039 0.001 0.005
General health 0.010 ¥ 0.119 0.007 0.012
Total R‐square (%) 40.1
R‐square change (%) 20.5
n 5247
*p<.05; §p<.01; ¥p<.001, a B, unstandardized regression coefficient, b beta, standardized regression
coefficient
75
Table 3: M
ultivariabele association of work conditions, psychosocial factors and perceived
health status on work
ability for workers with and without a chronic health condition
Work ability workers aged 45 years and older
without chronic health condition
with chronic health condition
Ba
Beta
b
95% CI for B
Ba
Beta
b
95% CI for B
Lower
bound
Upper
bound
Lower
bound
Upper
bound
Individual characteristics
Age (yr)
‐0.015 §
‐0.058
‐0.023
‐0.006
‐0.008
‐0.021
‐0.023
0.007
Gender (referen
ce = m
ale)
0.121§
0.048
0.045
0.198
0.025
0.007
‐0.102
0.152
Education (reference = low)
0.071
0.025
‐0.017
0.160
0.131
0.035
0.010
0.271
Work conditions
Occupation secretary vs executive
‐0.054
‐0.018
‐0.151
0.044
0.294 ¥
0.074
0.135
0.454
Occupation policy vs executive
0.048
0.017
‐0.049
0.145
‐0.034
‐0.008
‐0.207
0.140
Occupation m
anagem
ent vs executive
0.058
0.018
‐0.047
0.163
0.139
0.027
‐0.060
0.337
Work type: physical vs. m
ental job
dem
ands
‐0.097
‐0.019
‐0.259
0.065
‐0.331 *
‐0.052
‐0.581
‐0.080
Work type: both physical and m
ental vs
men
tal job dem
ands
0.017
0.006
‐0.068
0.102
0.029
0.008
‐0.108
0.166
Psychosocial factors
Work attitude
0.005 ¥
0.077
0.003
0.007
0.007 ¥
0.084
0.003
0.010
Coping: active problem focusing
0.035 ¥
0.077
0.021
0.049
0.046 ¥
0.072
0.022
0.070
Coping: avoidance beh
aviour
‐0.033 ¥
‐0.057
‐0.050
‐0.016
‐0.021
‐0.026
‐0.050
0.008
Co‐w
orker support
‐0.013
‐0.021
‐0.030
0.005
0.004
0.005
‐0.025
0.033
Community support
0.029 ¥
0.112
0.019
0.038
0.025 §
0.072
0.009
0.040
Organisational support
‐0.004
‐0.012
‐0.013
0.006
‐0.015 *
‐0.039
‐0.029
‐0.001
76
Table 3:continued
Work ability workers aged 45 years and older
without chronic health condition
with chronic health condition
Ba
Beta
b
95% CI for B
Ba
Beta
b
95% CI for B
Lower
bound
Upper
bound
Lower
bound
Upper
bound
Perceived health status
Physical functioning
0.006 §
0.053
0.002
0.010
0.008 ¥
0.084
0.004
0.012
Social functioning
0.005 §
0.069
0.002
0.008
0.008 ¥
0.114
0.004
0.012
Role limitations from phy. problems
0.003 ¥
0.075
0.002
0.004
0.005 ¥
0.116
0.003
0.006
Role limitations from emo. problems
0.002 *
0.048
0.000
0.003
0.003 §
0.081
0.001
0.005
Men
tal health
0.006 *
0.057
0.002
0.011
0.005
0.043
‐0.001
0.012
Vitality
0.020 ¥
0.214
0.016
0.023
0.015 ¥
0.139
0.009
0.021
Pain
0.002
0.024
‐0.001
0.005
0.004 *
0.048
0.000
0.007
Gen
eral health
0.005 ¥
0.065
0.003
0.008
0.015 ¥
0.165
0.011
0.019
Total R
‐square (%)
28.7
42.8
n
3395
1852
*p<.05; §p<.01; ¥p<.001, aB, unstandardized
regression coefficient, b beta, standardized
regression coefficient
Chronic health conditions and work ability
77
DISCUSSION
The presence of a chronic health condition was related to work ability irrespective of work
conditions and psychosocial factors among workers aged 45 years and older. The
association between the presence of a chronic health condition and work ability,
substantially changed trough the impact of the psychosocial factors. Perceived health
status was very strongly related to the presence of a chronic health condition and
explained its relation with work ability to a great extent. This is not surprising, taken the
fact that subscales of the SF‐36 are multi‐item scales which assess separate aspects of
health and these can better differentiate in health than a single item question. Substantial
differences in variables associated with work ability for workers with and without a
chronic health condition were not found. Psychosocial factors and perceived health status
were most strongly related to work ability for both groups than other variables in our
study. As workers with a chronic health condition reported lower mean scores for work
ability, these workers might have the most benefit by a policy focussing on enhancing
associated variables.
The impact of psychosocial factors on the relation between chronic health conditions and
work ability can be explained by the fact that these psychosocial factors indirectly
influenced both the chronic condition and the work ability. This finding corroborates with
results of previous studies, which found that the strategy to cope with (health) problems
was associated with disability and sickness absence38‐41. Social support has been shown to
be relevant predictors with regard to time to return to work for all types of health
conditions and a more positive attitude towards work was related to a better work ability
level42,43. Support at the work place and in private life were important determinants of
improved work functioning in previous studies17,44,45. One unanticipated finding in this
study was that increased co‐worker support was negatively related to work ability. This
counter‐intuitive result on co‐worker support might be explained by the fact that the
questions about co‐worker support measured expectations and incentives of colleagues
regarding continuing work due to illness. It might be that what we deemed to be co‐
worker support was sometimes perceived as social pressure, which results in a negative
association with work ability. Moreover, the subscale measuring co‐worker support
contained two self‐constructed questions and with unknown content and construct
validity.
The impact of work conditions, as operationalized in this study, was very small. This might
be explained by the particular choice of work‐related factors in our study. Work conditions
varying from role ambiguity, physical climate, work schedule, repetitive movements or
ergonomic conditions have been shown to be predictors of work ability23. The work‐
Chapter 4
78
related factors we used in this study did not focus on characteristics of work, but were
based on work conditions (such as sector, occupation, duration function, and shift work).
Future research should therefore be aimed at examining the influence of work conditions
on the association between the presence of a chronic health condition and work ability.
The variables associated with work ability for workers with and without a chronic health
condition were similar. However, the health variables and psychosocial factors were more
strongly related to work ability for workers suffering from a chronic health condition
compared to workers without a chronic health condition. Moreover, the perceived health
status was lower for workers with a chronic health condition. These findings suggest that
increasing the work ability level for workers suffering from a chronic disease might be
achieved by intervening on psychosocial factors and more importantly on perceived health
status.
To our knowledge, this is the first study to specifically investigate the impact of work
conditions, psychosocial factors and perceived health on the association between the
presence of a chronic health condition and work ability. Although the Work Ability
Questionnaire (WAI) has been used in several studies as the outcome measure to assess
work ability, in this study the first item was used. Whereas the total score of the WAI is
based on the number of chronic health conditions, it is inaccurate to use the WAI to
determine predictors of the association between chronic health conditions and work
ability. Therefore, in this study the single item measure based on the workers’ view of
current work ability compared to when it was at its best is used. A strength of the study is
that it was based on a considerable sample of workers with various occupational activities
(e.g. heavy physical labour, back office, health care, teaching and cleaning) employed in
different companies. The results of the study can therefore be generalized to a large part
of the working population of 45 years and older. Previous studies on the association
between psychosocial factors and work conditions on work ability have conducted in
specific occupational groups3,16,46. Moreover, psychosocial factors in earlier studies were
often actually work‐related such as job demands and lack of control. This study assessed
psychosocial factors based on individual resources like coping behaviour, work attitude,
and perceived support. A limitation of the study was that the cross sectional design does
not permit exploration of causal relationships between the factors on the association
between chronic health condition and work ability. Therefore, it remains unknown
whether, for example, increased co‐worker support was negatively related to work ability
or workers with a low work ability receive more social support from co‐workers.
Nevertheless, the results are still of interest as they provide a first insight into important
Chronic health conditions and work ability
79
factors to intervene on regarding work ability among workers aged 45 years and older
with or without a chronic health condition. Additional longitudinal (intervention) studies
are needed to examine causality. A second limitation concerns the fact that self‐report
was used to assess all the variables in this study. As a result, some misclassification of
respondents might have occurred which will most probably have been non‐differential
and thus have resulted in underestimations of the associations under study. However, it is
known from literature that self‐reporting of health status and of certain physical chronic
diseases (diabetes, cardiovascular disease, musculoskeletal and respiratory problems) is
reasonably reliable47. Therefore, we do not expect that the self‐reporting of health and
problems due to ageing introduced any significant bias for this kind of health conditions.
Thirdly, we cannot rule out that non‐response has influenced our results. The overall
response rate of 39% at baseline was regarded to be reasonable for an anonymous survey
in the working population. Because of the anonymous study design, we were not able to
investigate the characteristics of the non‐responders properly. We found that the
response rate in large organisations (> 4000 workers) was lower compared to the smallest
organisations (around 250 workers). Furthermore, we found differences regarding gender
(higher % response of male workers in production and female in health care and
education) and function (more executive workers in production, more policy and
management workers in telecommunication and government). This might be explained
due to sector differences, e.g more male workers in the production compared to health
care and education. Furthermore, the results of our study might not be representative for
workers in the production sector because of the underrepresentation of these workers in
our study. Finally, workers between 45 and 64 years who are still working might be a very
select, relatively healthy group of the general population of this age. This is known as the
healthy worker effect, a phenomenon which is often encountered in occupational
cohorts48,49. In this cohort of older workers the healthy worker selection is probably
stronger than in populations of workers of all ages, because of the many possibilities of
early retirement that were available for older workers in the last two decades. Because of
that the results from our study are probably an underestimation of the influence of
determinants on the association between the presence of a chronic health condition and
work ability.
CONCLUSION AND RECOMMENDATIONS
We found that psychosocial factors and especially perceived health status, rather than
work conditions, explain a large part of the decreased work ability of workers with a
chronic condition. Variables associated with work ability did not substantially differ for
Chapter 4
80
workers with and without a chronic health condition. Based on the lower mean scores for
workers with a chronic health condition for work ability as well for predictors, these
workers might have the most benefit by a policy focussing on enhancing these associated
variables. Given these results, it may be a promising approach to address perceived health
as well as psychosocial factors in strategies and interventions towards a sustainable
healthy working life. Previous studies found beneficial effects of the problem solving
approach on health and work related outcomes50‐52. Problem‐solving based interventions
might increase the workers awareness and behaviour by emphasizing their own decisive
role in attaining goals and giving them the feeling that they can be effective in carrying out
the necessary actions, with support from others. Future research to determine variables
associated with work ability for workers with and without a chronic health condition
should incorporate longitudinal designs and also include work characteristics such as
physical climate, work posture and work demands, as well as job control, decision
authority and work resources.
Chronic health conditions and work ability
81
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5
Coping, job control and social support as adaptation
determinants of work ability among ageing workers with and
without a chronic health condition
Submitted for publication
W. Koolhaas
M.R. de Boer
J.W. Groothoff
S. Brouwer
J.J. van der Klink
Chapter 5
86
ABSTRACT
Aim: To examine the association of different coping styles with work ability among
workers aged 45 years and older, and if these association might depend on the extent of
job control and support. Differences in associations between workers with and without a
chronic health condition were examined.
Methods: The data of this cross sectional study were obtained from 5730 workers in five
different sectors. Work ability was assessed with the work ability Index. The Utrecht
coping was used to assess active, emotional and avoidance coping styles. The presence of
a chronic health condition was assessed by self‐report. Multiple regression analysis were
used to examine association, and interaction effect of job control and support.
Results: Active coping is positively associated with work ability, whereas both emotional
and avoidance coping are negatively associated with work ability. No interaction effect of
job control and support were found. For workers with a chronic health condition, the
association between active coping and work ability is stronger, and job control had a small
but positive effect on this association.
Conclusion: An active coping style is the most effective way to adapt to the challenges to
enhance sustainable employability of ageing workers with and without a chronic health
condition.
Key terms: adaptation, ageing workers, chronic health condition, coping, sustainable
employability, work ability
Adaptation determinants of work ability
87
INTRODUCTION
Given the demographic reality of ageing societies in most parts of the world, it has
become essential to realize a sustainable and healthy working life for ageing workers. To
stay in balance with the work demands, most ageing workers have to adapt on several
levels. First, the process of ageing itself has an impact on physical and mental health
status1,2 and is significantly associated with a decreased work ability 3,4. Both health status
and work ability are predictive measures of future disability, sickness absence, future
health, and early discontinuation of working life5‐8. Secondly, ageing is associated with an
increased incidence of chronic health conditions9,10. In 2010 more than one in three
workers in the Dutch working population aged 45 years and older indicated a chronic
health condition2,11 and had to adapt to the consequences of this condition. Finally,
workers have to adapt to the ever faster changing world of work. This is a challenge for all
workers, but ageing workers have a higher probability of getting used to routines in their
working life that may be difficult to change. If ageing workers cannot adapt to these
factors their work ability will be threatened.
Health and work characteristics are important determinants of work ability.
Several studies have shown that these determinants account for only a proportion of the
variation in self‐reported work ability3,12‐14. Determinants associated with adaptation like
coping and conditions which might influence adaptation like job control and social support
may be important for predicting work ability and performance as well. There is some
knowledge about the impact of job control and social support on work ability15,16, but the
above mentioned constructs have not been studied extensively until now in relation to
work ability of ageing workers. Previous studies showed that coping was associated with
several work and work ability related outcomes such as health, job performance17,
stress18, disability18‐20, and job satisfaction21. An active problem‐focused coping style
generally has a positive impact on well‐being and health outcomes20,22,23, results in less
reported absences and fewer critical incidents and errors24, reduces sickness absence
(frequency, length and duration)25, and increased return to work26. Emotion‐focused and
avoidance strategies result in psychological and physical symptoms and an avoiding coping
style is related to both morbidity and multimorbidity27. Therefore, active coping style
seems to be in general the most adaptive and effective style to cope with the demands in
present economies and work organizations.
Job control enables workers to adapt and to cope with work challenges and
demands28. The job demand‐control (JDC) model assumes that job control buffers the
negative effect of job demands on health and well‐being through individual coping29‐31.
High control correlated significantly with high work engagement32, whereas low job
Chapter 5
88
control influences the retirement intention negatively, and strengthened the associations
of poor health and low work ability with retirement intentions6,33. In several studies the
JDC‐model was supported only in subgroups with an (pro)active copings strategy34‐36. This
stresses an interactive affect that active coping and job‐control, as an essential element of
the JDC model, might have. So, the concept of job control might be a second important
factor with respect to adaptation besides an active coping style for ageing workers to
continue their work in good health till reaching retirement age.
Social contextual factors may play a role in the process of adaptation too, as
adaptation is always accomplished in interaction between the individual and his context.
Support of co‐workers and supervisors in the work environment has been found to be an
important factor in this respect37‐39. Like job control, support tends to improve employee
health40 and can buffer the negative effects of job demands41‐43. In addition, social support
from the (work) environment influences the effect of coping strategies in many situations.
The effect of an active coping style on job satisfaction, and thereby on well‐being, has
been shown to be positively associated with the extent of co‐worker and supervisor
support44. Supervisors may be important providers of emotional and instrumental
support45. Therefore, it is plausible that the effect of active coping strategies will be
strengthened by instrumental support. In a similar way the inverse effects of emotion‐
focused and avoidance coping on work ability might be attenuated by emotional support.
As work ability is strongly related to a worker’s self‐rated health and the presence of
chronic health conditions1,46, the association between work ability and coping, and the
interaction effects of job control and social support, might be influenced by the presence
of a health condition. Recent studies indicate that coping related concepts are important
in chronic diseases e.g. chronic kidney disease47, and Parkinson disease48 Workers with a
chronic health condition are often confronted with functional deterioration and physical
disability and coping resources might become essential for managing the work demands49‐
51. Moreover, workplace activity limitations were related to increased reports of all types
of coping for workers with arthritis52.
In summary, the literature suggest a complex interplay between health, factors associated
with adaptation and work ability, but systematic analyses have been scarce. The aim of
the present study is to examine a) the association between coping styles and work ability
among workers aged 45 years and older, b) whether job control and support modify these
associations, and c) whether these associations are similar for workers with and without a
chronic health condition.
Adaptation determinants of work ability
89
More specifically, the following five hypotheses are formulated:
1. An active coping style is associated with a higher work ability, and emotion‐
focused and avoidance coping styles are associated with a lower work ability for
ageing workers;
2. The association of active problem‐solving coping with work ability is stronger for
ageing workers with higher levels of job control;
3. The association of active problem‐solving coping with work ability is stronger for
ageing workers with higher levels of instrumental support;
4. The negative association of expression of emotions and avoidance coping with
work ability is weaker for ageing workers with higher levels of emotional support;
5. The associations mentioned in hypotheses 1‐4 are stronger for ageing workers
with a chronic health condition compared to workers without a chronic health
condition.
METHODS
Study population and procedure
The data of this cross‐sectional survey study were obtained from workers aged 45 years
and older. Ten companies representing five different sectors (education, health care,
production industry, government and telecom), invited by their occupational health
physicians, agreed to participate in the study. A self‐administered questionnaire,
consisting of 132 items, was sent to all workers aged 45 years and older (N=14,565). All
companies enclosed a letter of recommendation. The voluntary nature of participation
and confidentiality of the information they provided was guaranteed. Four weeks after the
initial mailing, all workers received a written reminder. The data were collected in
February and March 2008.
The Medical Ethics Committee of the University Medical Center Groningen
approved the study design and deemed ethical review unnecessary due to the non‐
medical nature of the research. All participants signed informed consent.
Measures
Work ability was measured by the Work Ability Index (WAI) , a self‐administered
questionnaire comprising seven scales: (i) subjective estimation of current work ability
compared with lifetime best (0–10 points); (ii) subjective work ability in relation to both
physical and mental demands of the work (2–10 points); (iii) number of diagnosed
diseases (1–7 points); (iv) subjective estimation of work impairment due to diseases (1–6
points); (v) sickness absenteeism during the past year (1–5 points); (vi) own prognosis of
Chapter 5
90
work ability after 2 years (1 or 4 of 7 points); and (vii) psychological resources (enjoyment
of daily tasks, activity and life spirit, optimism about the future) (1–4 points)53. The final
WAI score was calculated by summation of all scale scores and can range from 7 to 49
points. Higher scores on the WAI indicate a better work ability. The reliability [54] and
validity [55] of the WAI are acceptable.
The Utrecht Coping List (UCL) was used to assess styles of coping56. This
questionnaire was designed to measure the coping strategies people use in stressful
situations. In this study we used the short version of the original 47‐item Utrecht Coping
List which include a selected number of dimensions and items and consisting of three
scales: (1) active problem‐focusing (five items), (2) expression of emotions (four items),
and (3) avoidance behaviour (four items). The internal consistencies as well as the test‐
retest reliabilities have been shown to be satisfactory56. The internal consistencies found
for active, expression of emotions and avoiding focused coping strategies in this study
were 0.84, 0.70, and 0.71 respectively.
Perceived support was assessed with a self‐constructed scale reflecting a person’s
perception of social support. The 14 items were answered on a five‐point Likert scale
(totally disagree to totally agree). A confirmatory factor analysis fitted an instrument with
two relevant subscales: 1) emotional support (six items), and 2) instrumental support (six
items). Higher scores indicate more support for both scales. The internal consistencies for
emotional, and instrumental support in this study were 0.70, and 0.72 respectively.
Job control was assessed with four questions from the PRODISQ, partly based on
Karasek’s job control demands57,58. The PRODISQ module contains four questions about
the possibilities to organise one’s own work, decision authority, learning new things and
the opportunity for personal development. Each question was rated on a four point scale
ranging from ‘never’ to ‘always’. Higher scores indicated a higher job control (range 4‐16).
Socio‐demographics were also assessed by questionnaire. The level of education
was operationalized as: no or primary education (no), lower vocational education (low),
intermediate secondary/vocational education (middle) or higher vocational education and
university level (high). Occupation was divided into four groups: executive, secretarial,
policy, and management. The five companies represent a variety of sectors, i.e. health
care, education, government, production industry and telecommunication. We defined a
chronic disease as ‘the subjective experience of a long‐term irreversible disease of more
than 3‐month duration’, which is in accordance with many other studies59,60. It was
assessed by asking the respondents the question: ‘Do you currently have a long‐term or
chronic disease of more than 3‐month duration without the prospect of recovery?’
(yes/no).
Adaptation determinants of work ability
91
Statistical analysis
Persons with one or more missing values on the WAI items were excluded from the
computation of a WAI total score according to the manual53. We tested whether persons
with missing values on any of the variables included in the analyses differed from the
persons that had complete data using t‐tests (coping variables, support variables, job
control, and age) and chi‐square tests (chronic health condition, gender, education, sector
and occupation). Persons who did not respond at all, were not included in these analyses,
because we did not have any data for these persons. Next, descriptive statistics were
derived by computing means and standard deviations (SD’s) for normally distributed
continuous variables, medians and interquartile ranges (IQR’s) for continuous variables
that were not normally distributed and numbers and percentages for categorical variables.
This was done for the total sample as well as for participants with and without a chronic
health condition separately.
We constructed several linear regression models in line with the hypotheses of
the study. In the first set of analyses, we examined the relation between active coping,
avoidance coping and expression of emotions on the one hand with the WAI on the other
hand. For each of the coping variables we assessed three models: model 1 was
unadjusted; model 2 was adjusted for age and gender; model 3 was additionally adjusted
for level of education, occupation and sector. In addition, we tested for interaction of
instrumental support and job control in the relation between active coping and work
ability, and of emotional support in the relations between avoidance coping and work
ability, and expression of emotions and work ability. This was done by adding interaction
terms to model 2 of the specific analyses. All regression analyses were performed for the
total sample as well as for participants with and without a chronic health condition
separately. An alpha < 0.05 was used to assess statistical significance for all analyses and
all analyses were performed in IBM SPSS statistics 20.0 (IBM Corp. released 2011, Armonk,
NY.)
RESULTS
Of the total response of 5,730 workers, 771 workers were excluded from the analyses
because of incomplete data on the variables used in the study. The final sample comprised
of 4,953 (34%) complete cases of surveys filled in by workers aged 45 years and older.
Those workers with missing values had a significantly lower mean age (‐0.50 years) and
significantly higher mean scores on active coping (0.83 points) and job control (0.68
points). Furthermore, the group of workers with missing values consisted of significantly
higher percentages of women (44% vs 32%), executive workers (60% vs 45%), production
Chapter 5
92
workers (21% vs 2,5%), no/lower educated workers (35% vs 22%), and less workers in
telecommunication (28% vs 51%), compared to those workers included in the study.
Table 1 shows a description of the baseline characteristics for the total sample and for
workers with and without a chronic health condition separately. The mean age of the total
sample was 53.0 years (SD=4.4) and 68% was male. Most workers were highly educated
(44%) and working in an executive function (45%). Half of the workers were working in the
sector telecommunication (50%), followed by working in the sectors education (23%) and
health care (20%). The presence of a chronic health condition was reported by 35.3% of
the workers (n=3,205). The mean work ability score was 39.6 (SD 5.9), with lower mean
scores for workers with a chronic health condition as compared with workers without a
chronic health condition (35.6 vs. 41.8). Mean scores on active coping (14.9, SD 2.6),
emotional coping (8.5, SD 1.9), avoidance coping (8.2, SD 2.0), job control (10.0, SD1.9)
and the instrumental (19.5, SD4.0) and emotional (24.0, SD4.7) support variables were
fairly similar for these two groups of workers.
For the total sample, the associations between the three coping styles and work ability
were all statistically significant and in the expected direction (Table 2). A more active
coping style was associated with a higher work ability (b=0.324; p<.001) and a more
emotional and avoidance coping style were negatively associated with work ability with
respectively b=‐0.243 ( p<.001) and (b=‐0.363; p<.001) (hypothesis 1). The results show no
statistically significant nor relevant interaction effects of support and job control on the
associations of active coping and work ability (hypotheses 2 and 3). There was also no
significant interaction effect of emotional support on the association of expression of
emotions and avoidance coping (hypothesis 4).
Adaptation determinants of work ability
93
Table 1: Baseline characteristics total population, workers with and without a chronic health condition Variable Total
(N=4953)
workers with a
chronic health
condition
(N=1748)
Workers without a
chronic health
condition
(N=3205)
Age in years (mean, SD) α 53.0 (4.4) 53.2 (4.3) 52.9 (4.5)
Gender (N, % male)β 3346 (68%) 1106 (63%) 2240 (70%)
Education β
No (N,%) 46 (1%) 20 (1%) 26 (1%)
Low (N,%) 1009 (20%) 423 (24%) 586 (18%)
Middle (N,%) 1718 (35%) 575 (33%) 1143 (35%)
High (N,%) 2180 (44%) 730 (42%) 1450 (46%)
Occupation β
Executive (N,%) 2231 (45%) 845 (48%) 1386 (43%)
Secretarial (N,%) 1018 (21%) 387 (22%) 631 (20%)
Policy (N,%) 988 (20%) 308 (18%) 680 (21%)
Management (N,%) 716 (14%) 208 (12%) 508 (16%)
Sector β
Production (N,%) 122 (3%) 50 (3%) 72 (3%)
Education (N,%) 1128 (23%) 416 (24%) 712 (22%)
Health care (N,%) 1002 (20%) 378 (22%) 624 (20%)
Government (N,%) 197 (4%) 63 (4%) 134 (4%)
Telecommunication (N,%) 2504 (50%) 841 (47%) 1663 (51%)
Work ability
Work ability (Mean, SD) α 39.6 (5.9) 35.6 (6.3) 41.8 (4.4)
Coping
Active (Mean, SD)α α 14.9 (2.6) 14.8 (2.5) 14.9 (2.5)
Emotional (Mean, SD) α 8.5 (1.9) 8.6 (2.0) 8.4 (1.8)
Avoidance (Mean, SD) α 8.2 (2.0) 8.4 (2.0) 8.1 (2.0)
Job control (Mean, SD) α 10.0 (1.9) 9.7 (1.9) 10.1 (1.9)
Support
Instrumental (Mean, SD) 19.5 (4.0) 19.3 (4.3) 19.6 (3.8)
Emotional (Mean, SD) α 24.0 (4.7) 23.4 (4.8) 24.3 (4.6)
α T‐test statistics shows significant differences (≤.001) between workers with and without a chronic
health condition, α α significant differences (≤.05), β Chi‐square statistics shows significant differences
(≤.05) between workers with and without a chronic health condition
94
Table 2: A
ssociation between coping styles and work ability for workers with and without a chronic health condition
Variable
Total (N=4953)
Workers with a chronic health
condition (N=1748)
Workers without a chronic
health condition (N=3205)
B
95% CI
B95% CI
B95% CI
Active coping model 1∞
0.441*
0.377‐ 0.505
0.513*
0.401‐ 0.625
0.349*
0.290‐ 0.409
Active coping model 2^
0.431*
0.367‐ 0.495
0.513*
0.401‐ 0.624
0.343*
0.284‐ 0.402
Active coping model 3
$0.324*
0.259‐ 0.390
0.424*
0.310‐ 0.537
0.268*
0.207‐ 0.330
Interaction with job control
0.016
‐0.014‐ 0.046
0.068**
0.016‐ 0.121
‐0.005
‐0.033‐ 0.024
Interaction with instrumental support
‐0.007
‐0.021‐ 0.008
0.009
‐0.015‐ 0.032
‐0.008
‐0.022‐ 0.006
Expression of em
otions model 1∞
‐0.179*
‐0.266‐ ‐0.091
‐0.078
‐0.224‐ 0.067
‐0.122**
‐0.207‐‐0.038
Expression of em
otions model 2^
‐0.176*
‐0.264‐ ‐0.087
‐0.086
‐0.233‐ 0.061
‐0.136**
‐0.222‐‐0.051
Expression of em
otions model 3
$‐0.243*
‐0.330‐ ‐0.156
‐0.138
‐0.282‐ 0.007
‐0.198*
‐0.282‐‐0.114
Interaction with emotional support
‐0.004
‐0.022‐ 0.013
‐0.011
‐0.039‐ 0.017
‐0.003
‐0.020‐ 0.014
Avoidance coping model 1∞
‐0.369*
‐0.450‐ ‐0.288
‐0.289*
‐0.434‐‐0.145
‐0.273*
‐0.348‐‐0.198
Avoidance coping model 2^
‐0.369*
‐0.450‐ ‐0.288
‐0.302*
‐0.446‐‐0.157
‐0.279*
‐0.354‐‐0.204
Avoidance coping model 3
$‐0.363*
‐0.443‐ ‐0.283
‐0.293*
‐0.437‐‐0.150
‐0.270*
‐0.344‐‐0.196
Interaction with emotional support
0.015
0.000‐ 0.031
0.001
‐0.026‐ 0.028
0.018**
0.003‐ 0.034
∞Model 1: u
nadjusted
^Model 2: adjusted
for age and gender
$Model 3: adjusted
for level of ed
ucation, occupation and sector
*p≤.001, **p
≤0.05
Adaptation determinants of work ability
95
When examining the relations for the two subgroups of ageing workers with and without a
chronic health condition separately (hypothesis 5), we found significant associations
between active and avoidance coping and work ability for both groups. For workers with a
chronic health condition, the association between active coping and the WAI were
stronger (b=0.424 versus b=0.268), whereas the associations between avoidance coping
and work ability were of similar magnitude (b=‐0.293 versus ‐0.270) compared with those
workers without a chronic health condition. For workers without a chronic health
condition expression of emotions has a negative impact on the association with work
ability (b=‐0.198). This negative impact was weaker (b=‐0.138) and not statistically
significant for workers with a chronic health condition.
Two statistically significant interaction effects were found. For ageing workers with a
chronic health condition the association between active coping and work ability was
modified by job control (b=0.068; p=0.011). This means that for workers with a five point
higher score on job control the regression coefficient for the relation between active
coping and work ability was 0.34 points higher. For ageing workers without a chronic
health condition, emotional support showed a positive interaction on the association
between avoidance coping and work ability (b=0.018; p=0.018), meaning that this relation
was weaker (less negative) for persons with higher scores on emotional support.
DISCUSSION
The results of our study confirm hypotheses 1 and 5. The relations between the three
coping styles and work ability were all statistically significant. An active coping style was
associated with a higher work ability, whereas expression of emotions and avoidance
coping were negatively associated with work ability (hypothesis 1). Contrary to our
hypotheses (2,3 and 4), no interaction effects of instrumental support and job control
were found. When examining the relations for ageing workers with and without a chronic
health condition separately, we found stronger associations between active coping and
work ability for ageing persons with a chronic health condition than for persons without
such a condition (hypothesis 5). The association between the coping style expression of
emotions and work ability was stronger for workers without a chronic health condition.
Job control strengthened the association between active coping and work ability for
workers with a chronic health condition, whereas emotional support buffered the
association between avoidance coping and work ability for workers without a chronic
health condition.
These findings indicate that in today's society, with its dominance for self‐
direction and its tendency to reframe problems as challenges, the active coping style is the
Chapter 5
96
most effective in the majority of situations for workers aged 45 years and older. As most
work situations are complex in present days economies this could be strengthened by the
fact that in ambiguous situations, a focus on one strategy might be more effective61.
In contrast to our second hypothesis, the association of active problem‐solving
coping with work ability was not strengthened by job control in ageing workers. These
results suggest that the relationship between active coping and work ability do not
become stronger with higher job control. We expected that job control as organizational
resource would enable ageing workers to cope in an active way. The job demand control
model of Karasek posits that control buffers the unhealthy effects of job demands on
health and well‐being and predicts that jobs combining high demands and high control
enhance opportunities for active coping strategies29. These null‐findings are in line with
previous studies by Shimazu (2004, 2005) in which job control did not change or buffer the
(negative) relation between active coping and outcomes like psychological distress or job
satisfaction44,45. A possible explanation might be that the level of controllability (mean
score job control of 10 on a range from 4 to 16) for the workers included in our study was
in balance with the needs and demands in the participating work organisations with as
consequence that we did not find the hypothesized interaction
Another finding was that we did not find the hypothesized interaction effect for
instrumental or emotional support on the relation between coping styles and work ability
for the total group. Based on the extended model of Karasek, it was expected that social
support would buffer the negative effect of job demands on health and well‐being, and
thereby work ability, through individual coping42,62,63. A review study on this model
reported that additive effects of social support on general psychological well‐being are
almost always found if the sample size is sufficient64. From previous studies it is also
known that supervisor support is an important predictor of work ability, especially for
workers with a chronic health condition15,65,66. In the present study we found no evidence
that this relation can be explained by facilitating active coping.
Distinguishing between ageing workers with and without a chronic health condition shows
that the relation between an active coping style and work ability is stronger for people
with a chronic health condition. The results of this study are consistent with previous
studies. These studies showed that persons with moderate to high impairment of physical
function and emotional well‐being reported more frequent use of active coping
strategies67 and that longer illness duration of patients with chronic fatigue syndrome
resulted in a higher use of an active coping approach68. This might be explained by the fact
that their health condition provides an extra (partly) controllable challenge to adapt to the
Adaptation determinants of work ability
97
work demands. A strong focus on the active coping style might almost be a prerequisite to
enhance their ability in controllable situations. The fact that expression of emotions has a
less negative effect for these workers with a chronic health condition might reflect that
their condition confronts them with incontrollable situations too, for which an expression
of emotions style might be adaptive61,69,70.
For workers with a chronic health condition we found that experienced job
control had a small but positive effect on the association between active coping and work
ability. Control over ones time scheme or the sequence in which tasks are performed, may
contribute to a successful adaptation to limitations as a consequence of the health
condition71,72. For workers without a chronic health condition, we found emotional
support to buffer the negative effect of an avoidance coping strategy. This is in accordance
with our hypothesis for the total group, but the effect is small.
To our knowledge, this is the first study to specially investigate determinants associated
with adaptation to enhance work ability. A strength of our study is that the results are
based on a considerable sample of workers with various job characteristics (e.g. job
demands and job control) employed in different companies. The results of the study can
therefore be generalized to a large part of the working population of 45 years and older. A
limitation of the study was that the current study is cross‐sectional in nature. This design
does not permit exploration of causal relationships between coping and work ability.
Nevertheless, the results are still of interest as they provide a first insight into the
determinants associated with adaptation for ageing workers with and without a chronic
health condition to enhance sustainable employability. Our design also automatically
meant that we used data from workers still working, who may present a select, relatively
healthy group of the general population of this age. Because of this selection, the data
from this study probably presents underestimations of the scores on all work related
outcomes in the entire group73,74. It is unclear whether and how this might have
influenced our results related to the postulated hypotheses, but bias might have occurred
in any direction. Second, the overall response rate of 39% at baseline is regarded to be
reasonable for an anonymous survey in the working population, but results related to
selective participation cannot be ruled out. Because of the anonymous study design, we
were not able to investigate the characteristics of the non‐responders properly.
Nevertheless, we believe there is no reason to expect that workers with ageing problems,
lower work ability or a chronic health condition returned the questionnaire less frequently
than workers without problems. The questionnaire addressed a variety of themes, and did
not emphasize functional ageing, chronic health condition or the outcomes work ability
Chapter 5
98
and coping. A third issue concerns the self‐reporting nature of the study because the
perception of workers’ responses could not be externally validated. As a result, some bias
may exist in the classification of respondents on the basis of self‐reported data, resulting
in an underestimation of the differences and associations under study. Finally, the current
study does not distinguish between specific chronic health conditions because of the lack
of knowledge of the severity and limitations of the conditions. It is possible that severely ill
and chronically disabled are in most cases excluded from working life and their
perspectives are not included in our sample.
In conclusion, this study indicates that in today's society with its dominance for self‐
direction and its tendency to reframe problems as challenges, the active coping style is the
most effective in the majority of situations for workers aged 45 years and older. This
seems especially true for workers with a chronic health condition. These workers can be
further supported in their adaptation by enhancing their job control.
On the individual level the adaptation of ageing workers can be strengthened by
stimulating them in adopting an active coping style. Interventions aimed at increasing the
awareness of workers of their responsibility and the possibilities they have to be actively
engaged in coping with work problems might enhance a sustainable working life.
Adaptation determinants of work ability
99
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6
Enhancing a sustainable healthy working life:
design of a clustered randomized controlled trial
BMC Public Health. 2010 Aug 6;10:461
W. Koolhaas
S. Brouwer
J.W. Groothoff
J.J. van der Klink
Chapter 6
106
ABSTRACT
Background: To improve a sustainable healthy working life, we have developed the
intervention ‘Staying healthy at work’, which endeavours to enhance work participation of
employees aged 45 years and older by increasing their problem‐solving capacity and
stimulating their awareness of their role and responsibility towards a healthy working life.
This research study aims to evaluate the process and the effectiveness of the intervention
compared with care as usual.
Methods/design: The study is a cluster‐randomized controlled trial design (randomized at
the supervisor level), with a 1‐year follow‐up. Workers aged 45 years and older have been
enrolled in the study. Workers in the intervention group are receiving the intervention
‘Staying healthy at work’. The main focus of the intervention is to promote a healthy
working life of ageing workers by: (1) changing workers awareness and behaviour, by
emphasizing their own decisive role in attaining goals; (2) improving the supervisors’
ability to support workers in taking the necessary action, by means of enhancing
knowledge and competence; and (3) enhancing the use of the human resource
professionals and the occupational health tools available within the organization. The
supervisors in the intervention group have been trained how to present themselves as a
source of support for the worker. Workers in the control group are receiving care as usual;
supervisors in the control group have not participated in the training. Measurements have
been taken at baseline and will be followed up at 3, 6 and 12 months. The primary
outcome measures are vitality, work ability and productivity. The secondary outcomes
measures include fatigue, job strain, work attitude, self‐efficacy and work engagement. A
process evaluation will be conducted at both the supervisor and the worker levels, and
satisfaction with the content of the intervention will be assessed.
Discussion: The intervention ‘Staying healthy at work’ has the potential to provide
evidence‐based knowledge of an innovative method to promote a sustainable healthy
working life in the older working population. The results of the study will be relevant for
workers, employers, occupational health professionals and human resource professionals.
Trial registration: The trial is registered with the Dutch Trial Register under number
NTR2270.
The development of an intervention
107
BACKGROUND
Ageing of the workforce exerts pressure on society with respect to health, wealth and
social insurance systems, which are inextricably linked1. Older workers are more
vulnerable in the labour process, because of vitality and ageing problems affecting their
daily performance and their ability to meet job competence requirements2‐6. Ageing is
associated with a higher sickness absenteeism rate7, reduced work ability and decreased
productivity8‐10. Most societies are geared to retirement at around 65 years of age. An
inability to meet work demands, due to ageing, forces older workers to leave the labour
market before reaching retirement age11,12. In addition, the age of the working population
is declining13. This situation affects government budgets and social securities, and puts
pressure on the current arrangements for public pensions and healthcare11,12.
The nature of work has changed over recent years due to globalization and
information technologies (the ‘new economy’) in the Organisation for Economic Co‐
operation and Development (OECD) countries, and work‐based life‐long learning is
required14. Moreover, the more dynamic market and shorter product cycles have resulted
in fewer jobs, with frequent job changes over a working lifetime14. To keep workers in the
labour market during the coming decades, employers should invest in education for and
training of their employees, and the implementation of policies and working methods to
enable workers to have the necessary competencies for longer working lives12,15. Due to
these changes in the labour market, the employee–employer relationship has evolved
from one of mutual loyalty to one based on personal gain. Workers are increasingly
responsible for their own career, and they need to be aware of their own responsibility
and decisive role in creating and/or maintaining a healthy work life. Most intervention
studies to promote workers’ health to extend working life, provide a lifestyle training
programme, for a specific group of workers, to improve job retention16, increase vitality17
or decrease work disability and sickness absenteeism18‐21. However, to gear the work
demands and activities to the personal capabilities of the worker, in order to maintain and
promote sustainable work participation, a strategy for older workers to solve problems
with regard to ageing and chronic health conditions is required, involving good
cooperation between the supervisor and the employee22‐24. We have therefore developed
an intervention to improve a healthy sustainable working life for workers aged 45 years
and older.
Our intervention is called ‘Staying healthy at work’. The goal of the intervention is to
promote a healthy sustainable working life of older workers until retirement age by: (1)
changing workers awareness and behaviour by emphasizing their own decisive role in
Chapter 6
108
attaining goals and giving them the feeling that they can be effective in carrying out the
necessary actions; (2) improving supervisors’ ability to support workers in taking the
necessary actions by means of enhancing knowledge and competencies; and (3)
enhancing the use of human resource professionals (HRPs) and occupational health tools
available within the organization.
The rationale of the intervention is based on theoretical models and theories, on
the results of a survey study of workers aged 45 years and older and on four expert
meetings. A detailed description of the development of the intervention is presented in
the Appendix (additional file 1). The primary aim of this intervention study is to evaluate
the effectiveness of the ‘Staying healthy at work’ intervention compared with care as
usual (CAU) on productivity, vitality and work ability. We hypothesized that after
undergoing the intervention, older workers would improve sustainable work participation
by using problem‐solving strategies with regard to health problems or opportunities to
create a healthy work situation compared with workers who received CAU. The secondary
aims are to improve work attitude, self‐efficacy and work engagement, and to decrease
fatigue and job strain. A process evaluation will be conducted among workers and
supervisors. To our knowledge, this is the first study focusing on a sustainable healthy
working life.
METHODS/DESIGN
The methods and design of the intervention study are as described in the CONSORT
statement and the extension for cluster‐randomized trials25,26.
The study is designed as a two‐armed cluster‐randomized controlled trial (RCT) with a 1‐
year follow‐up. In the study, the intervention group will be compared with CAU (Figure 1).
Eligible workers could not be randomly assigned to supervisors in the intervention group
or supervisors randomly assigned to eligible workers in the control group, because the
supervisor and worker are bound to each other by their department. Moreover, training
all supervisors before randomization was not possible because of the risk of data
contamination. Therefore, cluster randomization was applied at the supervisor level27.
Supervisors at the same department have been placed in either the intervention or the
control group. Workers with their supervisor in the intervention group have been
allocated to the intervention group, and workers with their supervisor in the control group
have been allocated to the control group.
The Medical Ethical Board of the University Medical Center of Groningen
informally approved the study design. They decided that this study did not need an ethical
The development of an intervention
109
approval, because this study did not perform clinical research with medicinal product for
human beings according to the Dutch law. Workers could participate voluntarily in this
study, and they are free to leave the study at any time without further consequence. All
workers signed an informed consent to participate in the study.
Study population
Recruitment of participants took place at the University and the University Medical Center
of Groningen. The source population consisted of workers aged 45 years and older from
different departments: intensive care, administration, personnel and executive workers.
Workers on long‐term sick leave with no prospect of recovery, or workers who left the job
within 1 year because of illness or pension have been excluded from the study.
Recruitment of the supervisors
Supervisors at the departments proposed by the HRPs were invited to participate in the
study. Supervisors who were interested in the intervention method and were willing to
participate in the study received information about the procedure.
Procedure
The supervisor informed the workers of the upcoming intervention. Hereafter, the
workers received a letter of invitation to participate in the study, describing the aim,
content and set‐up of the study. Workers were invited to return a signed informed
consent to confirm their participation. Workers who were willing to participate in the
study received a baseline questionnaire (paper version) and a postage‐paid envelope.
Chapter 6
110
Figure 1: Study design. Overview of the study design of the intervention
Recruitment of the supervisors
Supervisors randomly allocated to the
intervention or the control group
Training of supervisors No training of supervisors
Informed consent and baseline
questionnaire
Informed consent and baseline
questionnaire
Recruitment of workers by the
supervisors
Recruitment of workers by the
supervisors
Care as usual Intervention
Follow‐up questionnaire
at 3, 6, and 12 months
Follow‐up questionnaire
at 3, 6, and 12 months
The development of an intervention
111
Intervention
Supervisor training in the intervention group
The supervisors received training before the implementation of the intervention, which
consisted of two components. The first training of 2 hours focused on knowledge
regarding a sustainable healthy working life, and on problem‐solving techniques. After 2
weeks, the second training took place, which consisted of an active training module in
which the problem‐solving techniques were taught, and practiced by role play. In this 5‐
hour training module, the trainer was assisted by an actor. The supervisors were trained in
skills to support the worker in basic problem‐solving techniques. A structured method for
identifying problems, solutions and applications of the solutions was offered, and skills to
guide the worker in using this method were taught. Moreover, the supervisor was trained
on how to present him‐ or herself as a source of support for the worker; not by taking
over responsibilities, but by strengthening the autonomy of the worker. Furthermore, the
supervisors received an overview of HRP and occupational health tools available within
the organization, such as work adjustments, training and education. This should help them
to advise their workers about which tools they could use to optimize work capacities and
personal development, and thereby work participation.
Intervention for workers in the intervention group
Step 1: inventory of problems, solutions and degree of changeability
Workers in the intervention group received a booklet. The content of the booklet was
based on the problem‐solving strategy described by Fontana28 and modified by van der
Klink29,30. The booklet is designed by the researchers to help with clarifying and exploring
problems with work functioning, working career and support needs, and stimulate
workers to think about possible solutions. In the booklet, examples of problems at work
due to ageing and support needs, possible solutions, and their role and responsibility in
creating a sustainable working career are described. The workers made an inventory of
experienced problems, barriers and support needs, including concrete examples of work
situations in which these problems occur. In addition, workers could indicate career
aspirations. Hereafter, workers determined the degree of changeability of each described
point. Workers needed to consider which changes they could realize by themselves, either
by changing the situation or by mobilizing support (e.g. supervisor, occupational physician,
social worker or psychologist), or, when the situation could not be influenced, by learning
how to cope with it, and accepting it. The booklet was sent to the supervisor after
finishing these first steps.
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Step 2: dialogue between worker and supervisor
The worker’s inventory in the booklet was the input for the dialogue between worker and
supervisor. The dialogue took place within 3 months of sending the booklet to the
workers. During the dialogue, the supervisor helped to establish the worker’s experienced
problems in work functioning, goals and solutions, on the process level. After identifying
problems with work functioning, support needs and defining career opportunities, a
concept action plan was made after brainstorming about the possibilities, actions and
responsibilities of both the worker and his supervisor.
Step 3: Action plan
After the dialogue with the supervisor, the worker made an action plan for the next 1‐year
follow‐up period. The booklet that workers received before the dialogue contained an
example of an action plan format to help workers to create their own action plan. Within 2
weeks of the dialogue, the worker had to complete this action plan, including the solutions
discussed with the supervisor. Workers are responsible for the execution of these actions
during the following year – when necessary, with the support of the supervisor or other
professionals. After 1 year, during the next annual assessment between worker and
supervisor, the action plan will be evaluated and both results and process will be
discussed.
Treatment of the control group
The supervisors in the control group did not receive training. If the intervention ‘Staying
healthy at work’ proves to be effective, the supervisors in the control group will be trained
in the future. Workers in the control group are being given CAU, which implies no
structured support, but the possibility of counselling or support by HRPs or other
professionals as required, or participating in training and human resource tools.
EFFECT EVALUATION
To investigate the effectiveness of the intervention ‘Staying healthy at work’, all workers
received a baseline questionnaire, and follow‐up questionnaires are to be filled in at 3, 6
and 12 months.
Socio‐demographic variables
At baseline, socio‐demographic data (gender, age, level of education, nature of work,
current work status, working hours a week) have been collected.
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Primary outcome
The primary outcomes of the study are: work ability, vitality and productivity.
Work ability
Work ability is being measured by the Work Ability Index (WAI)31, a self‐administered
questionnaire comprising seven scales: (1) subjective estimation of current work ability
compared with lifetime best (0–100 points); (2) subjective work ability in relation to both
physical and mental demands of the work (2–10 points); (3) number of diagnosed diseases
(1–7 points); (4) subjective estimation of work impairment due to diseases (1–6 points);
(5) sickness absenteeism during the past year (1–5 points); (6) own prognosis of work
ability after 2 years (1 or 4 of 7 points); and (7) psychological resources (enjoyment of daily
tasks, activity and life spirit, optimism about the future) (1–4 points). The final WAI score
is calculated by summation of all scale scores and can range from 7 to 49 points. The
reliability and validity of the WAI are acceptable32,33. Higher scores on the WAI indicate a
better work ability. Based on this WAI score, the individual’s work ability can be classified
into four categories: poor (7–27 points); moderate (28–36 points); good (37–43 points);
and excellent (44–49 points).
Vitality
Improvements in health‐related outcomes are being evaluated with the self‐reported 12‐
Item Short Form Health Survey (SF‐12), an abbreviated version of the 36‐Item Short Form
Health Survey34‐36. The SF‐12 provides two summary scores, the Physical Component
Summary (PCS) score, which represents what a person can do, and the Mental Component
Summary (MCS) score, which represents how a person feels. The mean PCS and MCS of
the general population are 50, with a standard deviation of 10. A higher score means a
better quality of life.
Productivity
Productivity is being measured with the QQ method, which aims at measuring the
quantity and quality of work performed on a daily basis37. The workers indicate how much
work they actually perform during regular hours on their last regular work day during a
working week as compared with a normal week day. The quantity of productivity is
measured on a 10‐point rating scale with 0 representing ‘nothing’ and 10 representing
‘normal quantity’. Meerdings et al.9 showed that self‐reported productivity in the QQ
measurement correlated significantly with objective work output.
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Secondary outcome
The secondary outcomes of the study are changes in fatigue, psychosocial work
characteristics, work attitude, self‐efficacy and work engagement.
Fatigue
To determine the level of fatigue, we are using the Checklist Individual Strength (CIS) [38].
The CIS is a 20‐item well‐evaluated questionnaire for the working population, measuring
four aspects of fatigue in separate scales. In this study, the subscale of the subjective
feeling of fatigue (eight items) is being used. The items are scored on 7‐point Likert scales
ranging from ‘Yes, that is true’ to ‘No, that is not true’. Higher scores on the separate
scales indicate higher degrees of fatigue38.
Psychosocial work characteristics
The Job Content Questionnaire (JCQ) is a self‐administrated questionnaire designed to
measure job strain39. The domains assessed are job demands (5 items), decision authority
(3 items), skill discretion (6 items), social support from supervisors (4 items) and co‐worker
support (4 items). Each domain is rated on a 4‐point scale from ‘strongly disagree’ (most
negative) to ‘strongly agree’ (most positive). The reliability of the scales is good40.
Work attitude
Perceived work attitude is being measured with a Dutch language version of the Work
Involvement Scale (WIS‐DLV), reflecting the degree to which a person wants to be
engaged in work41. The questionnaire consists of six items; with responses on a 1–4 point
scale (strongly disagree, disagree, agree, strongly agree). Higher scores on the WIS‐DLV
indicate more positive attitude towards work.
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Self‐efficacy
Self‐efficacy is being measured with the standardized Dutch version of the General Self‐
Efficacy Scale42, assessing the subjects’ expectations of their general capacities43. This 16‐
item questionnaire incorporates three subscales: willingness to exert effort in completing
the behaviour, persistence in the face of adversity, and willingness to initiate behaviour. It
consists of five response items (ranging from disagree to agree); higher scores indicate a
higher self‐efficacy.
Work engagement
Work engagement is being measured by a short Dutch version of the Utrecht Work
Engagement Scale (UWES‐9), which enquires how often the respondents currently
experience positive emotions at work44. The UWES‐9 consists of nine items rated on a 7‐
point scale ranging from ‘never’ (0) to ‘always/every day’ (6). The items are divided into
the subscales vigour, dedication and absorption. A total score is obtained by averaging the
individual item scores (possible range 0–6). The internal reliability and validity of the
Dutch UWES‐9 are acceptable45.
Process evaluation
The process evaluation will examine the applicability to implement the intervention
‘Staying healthy at work’ at both the supervisor and the worker level. The supervisors in
the intervention group received a questionnaire before and will receive one after the
training to examine the quality of the training, the content of the training, and the added
value of the training, as a strategy to improve the communication with the workers
regarding work participation and work functioning.
Among the workers of the intervention group, experiences with the use of the
intervention will be evaluated in the follow‐up questionnaires. Workers were asked to
evaluate the content and the relevance of the information leaflets and the booklet to
prepare for the dialogue. Also the dialogue with the supervisor will be evaluated in the
questionnaire after 3 months. All follow‐up questionnaires contain items about the
support of the supervisor, the contribution of the booklet to help make an inventory and
action plan, and the workers’ experiences with the problem‐solving strategy to stimulate
communication about work performance. In addition, questions will be asked about the
enhanced problem‐solving capacity and awareness with regard to the workers’ own role
and responsibility towards a healthy and motivating work situation. Workers will also be
asked to evaluate whether the work‐related situations they wanted to improve have
actually improved, whether they had used HR tools, training, education or contacted
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professionals during the intervention and if they had attained the goal they had in mind at
the start of the intervention. Both workers and supervisors received questions at the
baseline and will receive follow‐up questionnaires about the readiness for change
concerning the intervention.
Reasons for complying or not complying will be asked in the follow‐up workers’
questionnaire as well, in order to gain insight into the potential success of
implementation.
Statistical analyses
All analyses will be performed according to the intention‐to‐treat principle. Baseline
characteristics of workers will be analyzed for differences between the intervention and
the control groups. Differences between the intervention and the control groups in
changes on the outcome variables will be performed with multi‐level longitudinal analysis.
Intra‐cluster correlations will be determined for all primary outcome variables. Effects of
the intervention will be controlled with covariates, such as gender and job type. Further
analyses will include the comparison of the secondary outcomes at follow‐up between the
two arms. For all analyses a two‐tailed significance level of p<0.05 is considered to be
statistically significant. All analyses will be carried out with the statistical package SPSS
version 16.0 (SPSS Inc. Chicago, IL, USA).
Power calculations and sample size
Work ability, measured with the Work Ability Index (WAI) [46] is the primary
outcome measure for the power calculation. The range of the summative index of the WAI
is 7–49, which is classified into four subgroups: poor (7–27), moderate (28–36), good (37–
43), and excellent (44–49)31. The target of this intervention study is to increase the mean
scores of the workers to those of the next subgroup. This implies a minimum increase of
5.4 (24%) for workers with a poor work ability, and minimum increase of 3.7 (11% and 9%,
respectively) for workers with a moderate and good work ability before the intervention.
For the workers with an excellent WAI score at baseline, the aim is to maintain the score.
The survey study demonstrates that the effect size of workers is high (≥0.80).
We used Optimal Design47,48 to calculate the optimal sample size by a power of
0.80 for testing the treatment effect in this cluster‐randomized trial with an intervention
and a control group in a repeated measurement design. A literature search on the role of
the supervisor to the worker’s attitude24,49 showed an intra‐class correlation (ICC)
between 0.11 and 0.26 for supervisors. We used the most extreme value (ICC = 0.26) for
the power calculation. A total of 20 supervisors are enough to reach a power of 80%.
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Calculating from 80% power (two‐sided, alpha = 0.05, 20 supervisors) a sample
size of eight workers per supervisor are needed to determine a significant difference
between the intervention and the control groups. The eight workers must be viewed as
the average number of workers per supervisor. This requires at least 80 workers in each
group. Allowing for a loss to follow‐up of 15%, a sample size of 92 workers (in each group)
is required.
Blinding
The validity of the study will be compromised if information is known about the
intervention in the control group. To minimize data contamination, pre‐randomization at
the supervisor level is applied for allocating the workers into the intervention or the
control group. Therefore, different information about the study can be provided to
workers in the intervention and the control groups27. Workers in the control group do not
know the content and design of the intervention ‘Staying healthy at work’. Whereas
workers in the control group are blinded to the intervention, blinding of the supervisors
was not possible. Supervisors in the control and the intervention groups have been
informed about the content of the intervention, because they already knew the set‐up of
the study prior to their decision to participate.
DISCUSSION
The results of this cluster‐randomized controlled study will provide input for an evidence‐
based intervention which may improve a sustainable healthy working life of workers aged
45 years and older. The intervention offers a structured method for workers to
communicate with their supervisor about their work environment, barriers to work
performance and career opportunities. Aspects concerning intervention procedure are
described in the protocol; however, supervisors and workers are free to choose specific
tools at each phase of the process. We assume that such a structured (non‐protocol)
intervention strategy giving workers the opportunity to make an action plan for the next
1‐year follow‐up period, will be an effective way to create a sustainable, healthy, working
life for older workers. Moreover, this method has been shown to be effective in
shortening sick‐leave duration by workers on their first sick leave50.
Strengths
One of the main strengths of the intervention ‘Staying healthy at work’ is that it offers a
strategy to improve the problem‐solving capacity of both workers and supervisors. The
workers will be trained to be aware of their own decisive role in attaining goals, and they
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will learn how to cope with future problems related to work participation. The skills of the
supervisors will be improved by strengthening the workers’ ability to act and make
decisions autonomously, and to not take over the workers’ responsibilities. Additional
value of the intervention is that the method will contribute to the annual assessment,
between supervisor and worker, of work functioning and participation. The intervention
method can be incorporated into the annual worker assessments within the organization.
Another strength of the intervention is the close cooperation with the HRPs during the
development of the intervention. This offers a tool and a process that fit in with the
existing company policy and improves the likelihood of effectiveness of the intervention.
Furthermore, the intervention will contribute to the knowledge and the use of the current
tools, education and training within the organization to enhance work participation.
Although many organizations have these tools available in their current policy, supervisors
and workers are often unaware of the opportunities they have aimed at improving the
working environment. The fact that the perspectives of the workers on work functioning
will be taken into account is also a strength of this study. We presume that this will lead to
a better compliance of the workers to participate actively in the intervention programme.
This will improve the effectiveness of the study. Finally, the cluster design of the study
reduces the risk of data contamination between workers in the intervention and the
control groups. Supervisors are randomly assigned to the intervention or the control
group. Pre‐randomization enables workers in the intervention group to be informed
separately, and therefore makes it possible to blind the workers in the control group to
the study condition.
Weaknesses
The variations between the supervisors is a drawback of the design. Supervisors in the
intervention group are trained to apply the problem‐solving capacity strategy and to
present themselves as a source of support to the workers. Variation between supervisors,
such as differences in knowledge, capabilities, experience with communication,
personality and readiness for change, can influence the results of this study, because of
the decisive role of the supervisor during the dialogue between worker and supervisor.
The process evaluation of the current study will give insight into the role of the supervisor
during the dialogue and the follow‐up of the study. Furthermore, a longer follow‐up than
the 12 months, as planned in the design, is preferable to investigate longer term
intervention effects on a sustainable healthy working life. Workers make an action plan for
the coming year based on one or two points of the inventory of problems, support needs
and working career in the booklet. One year later, during the next dialogue between
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119
worker and supervisor, the actions will be evaluated and both results and the process will
be discussed. In addition, they make an agreement about the next action to optimize work
performance. Therefore, it would be advisable to follow the workers for more than 12
months. Another limitation of our study is that the evaluation of effect consists of
measuring enhanced work ability, vitality and productivity. Moreover, no economical cost‐
effectiveness evaluations are included.
Relevance of the study
To pro‐actively address the issue of a shifting workforce composition, companies must
anticipate and identify workforce issues within their organizations, and also develop
strategies to effectively mitigate any workforce‐related risks. A healthy working life
requires close attention being paid to each workers’ life‐cycle phase (learning, applying,
providing and diminishing) and individual demographic characteristics, such as age and
health. A policy to provide a diverse, challenging and balanced working life is needed to
increase knowledge, motivation and thereby participation. This study is focusing on
enhancing the problem‐solving capacity of workers to enhance work participation. The
intervention ‘Staying healthy at work’ is not only designed to enhance work participation,
but also to enhance the workers’ resources and capabilities to continue working in good
health until retirement.
Abbreviations HRP(s) = human recourse (management), CAU = care as usual, WAI = work ability index, PCS =
physical component summary, MCS = mental component summary, QQ = quantity and quality, CIS =
checklist individual strength, JCQ = job content questionnaire, WIS = work involvement scale, UWES
= Utrecht work engagement scale, ICC = intraclass correlation.
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ADDITIONAL FILE 1
Development of the intervention; Specification of the development of the intervention.
To determine the content of the intervention, the following steps were taken: literature
search, survey study and consultant meetings. Based on this information, we defined the
three objectives of the intervention.
Literature search
The rationale of the intervention is based on a number of theories and models: problem‐
solving, empowerment and behavioural change models.
The problem‐solving strategy is described in the guideline ‘Management of mental health
problems of workers by occupational physicians’ of the Netherlands Society of
Occupational Medicine29,30. The goal of the guideline is to support workers to control their
own functioning in the work situation. A structured strategy for identifying problems,
solutions and applications of solutions offers the workers the tools to increase their
problem‐solving capacity. This strategy helps them to find out that they can always
influence the impact of a situation by: (1) changing the situation by themselves; (2)
mobilizing the support of others; or (3) accepting the situation [30]. It contributes to the
workers’ belief that they are capable of performing in a certain manner to attain goals,
and thereby strengthens the their self‐efficacy51,52. The guideline has been shown to be
effective in shortening the sick leave duration of employees who are on long‐term
sickness absence because of mental health disorders50,53.
The empowerment philosophy is based on the premise that human beings have the
capacity to make choices themselves and are responsible for the consequences of their
choices54. Varekamp and Crawford Shearer55,56 show that empowerment‐based
interventions improve health, with purposeful participation in goal attainment and
wellbeing. Empowered workers are able to instigate changes in their personal behaviour
and social situation, and also to influence the organization environment they work for54.
Behavioural change models are frequently used in the development and implementation
of health‐promoting interventions57‐60. An example of a determinant model that has been
applied to various types of health‐related behaviour is the Attitude – Social influence –
self‐Efficacy (ASE) model derived from the theory of planned behaviour51 and the social
learning theory52. The ASE model is based on the assumption that the intention to engage
in behaviour is the result of goal attitude (the positive and negative evaluation of the
expected outcome of a certain behaviour), subjective norms (the belief about what others
think of the behaviour, as derived from the behaviour and/or direct feedback of significant
others), and self‐efficacy (the confidence in being able to carry out a set of specified
Additional file
121
activities) towards performing the specific behaviour. The influence of the ASE model on
the intention to change behaviour has been examined in several studies. Research shows
that the ASE model predicts changes in injury‐preventing behaviour58, eating behaviour60,
changes in physical activity57,59 and the intention to return to work after sickness leave61.
Obviously, an ASE‐based intervention is aimed at changing the determinants for intention
into behaviour and to remove the barriers to performing the desirable behaviour.
Finally, the International Classification of Functioning, disability and health (ICF) has been
a useful framework to classify and interpret relevant aspects with regard to disability and
participation62,63.
Survey of the problems, barriers, facilitators and support needs due to ageing
A survey study has been conducted to gather information about the problems
experienced in work performance due to ageing, barriers and facilitators in the work
situation and support needs to continue throughout the working life of workers aged 45
years and older64. Problems due to ageing, with regard to a sustainable working life, were
reported by 41% of the workers; 37% reported a chronic health condition. Barriers to
performing work tasks were reported by 59% of the workers who experienced problems
due to ageing, and to continue working life in the coming years, 68% of the workers
reported support needs. Most frequently reported barriers to work participation are
physical problems (muscle function decline), cognitive problems (concentration lapses and
memory deterioration) and mental problems (energy‐driven functions based on
psychological and physiological mechanisms) due to ageing. The most frequently
experienced barriers were concentration, work‐pace and mobility; facilitators are support
from colleagues and supervisors, and opportunities for personal development. The results
show that factors to enhance the working life of workers aged 45 years and older are
found at the personal and the organizational levels. These findings emphasize the need for
a joint – organization and worker – approach.
Consultant meeting group
Based on the literature search and survey study, a concept of the intervention has been
developed and discussed during consultant meetings with experts in the field of work and
health. First the content and practicability of the intervention were discussed in one
session with two senior researchers (from national institutes with experience of
occupational health intervention programmes) and two practising occupational health
physicians. The importance of informing workers about the research as well as the content
and organization of the study were discussed during the meeting. After revision of the
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recruitment procedure and the outcomes to define a sustainable working life, a meeting
with the head of the human resources department of the participating organization took
place. During this meeting, the importance of paying attention to the ageing workforce
was presented, especially the benefits of sustainable healthy workers and the possibility
of integrating the intervention into the current human resources system. This meeting led
to some restrictions on the implementation of the intervention, namely the number of
participants, the preference of participating departments, caused by the high percentage
of older workers, and the selection on the suitability of the department, based on the
current atmosphere. In addition, departments undergoing other types of intervention
studies were excluded from our intervention study. The HRPs recommend measuring and
supporting the use of current tools, education and training, to enhance work adjustments
and personal development, because these tools are currently underused by workers.
After the second revision of the intervention, managers and supervisors at the proposed
participating organizations were informed about the content of the intervention and the
research project by their HRP. The managers and supervisors at the eligible departments,
i.e. departments with the highest percentage of workers aged 45 years and older, were
recruited by their HRPs. The researchers sent an information leaflet by post to these
managers and supervisors, and consulted with all departments interested in participating
in the study about the content of the intervention. Some parts of the concept intervention
were omitted due to lack of support of the managers or supervisors, i.e. participation of all
ages and a 2‐day training of the supervisor.
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123
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7
Effectiveness of a problem‐solving based intervention to
enhance sustainable employability of ageing workers
Submitted for publication
W. Koolhaas
J.W. Groothoff
M.R. de Boer
J.J. van der Klink
S. Brouwer
Chapter 7
128
ABSTRACT
Objective: The aim of the current study is to evaluate the effectiveness of the problem‐
solving based intervention ‘Staying healthy at work’ compared to usual business.
Methods: This study was designed as a quasi‐experimental trial with a 1‐year follow‐up.
Measurements were performed at baseline, three and 12 months. The problem‐solving
based intervention provides a strategy to increase the awareness of ageing workers with
regard to their role and responsibility to create a sustainable healthy working life. The
primary outcomes were work ability, vitality and productivity. Secondary outcomes were
perceived fatigue, psychosocial work characteristics, work attitude, self‐efficacy, and work
engagement.
Results: Analyses were performed for 64 workers in the intervention and 61 workers in the
usual business group respectively. No effects on productivity and adverse effects on work
ability (B=‐1.33, 95%CI ‐2.45 to ‐0.20) and vitality (OR=0.10, 95%CI 0.02‐0.46) were found.
Positive results were found for the secondary outcomes work attitude (B = 5.29, 95%CI ‐
9.59 to ‐0.99), the self‐efficacy persistence subscale (B = 1.45, 95%CI 0.43‐2.48) and
subscale skill discretion of the psychosocial work characteristics (B = 1.78, 95%CI 0.74‐
2.83).
Conclusion: The results of the problem‐solving intervention showed no positive effects on
the three outcome measures compared to usual business. However, effectiveness was
shown on three of the secondary outcome measures, i.e. work attitude, self‐efficacy and
skill discretion. We presume that the lack of positive effects on primary outcomes is due
to program failure and not to theory failure.
Trial registration: The trial is registered with the Dutch Trial Register under number
NTR2270.
Key words: aging workforce, intervention study, ageing workers, problem‐solving
approach, solution focused, work ability
Effectiveness of the intervention
129
INTRODUCTION
Ageing of the workforce exerts pressure on society with respect to health, wealth and
social insurance systems1. Ageing is associated with a higher sickness absenteeism rate2,
reduced work ability and decreased productivity3,4. Moreover, ageing of the workforce is
associated with an increase in number of workers with chronic health conditions. There is
evidence that the presence of chronic health problems impacts on work ability5, work
disability6 and productivity4 while adjusted for age. The ageing workforce in combination
with the increase in health problems in ageing workers implies the importance of
evidence‐based interventions to enhance sustainable employability7. To date, this type of
interventions is scarce.
An important first step in developing strategies and preventive measures aimed at
maintaining and enhancing sustainable employability of ageing workers is to get insight
into the hindering and facilitating factors. In a recently published study we gathered
number and type of perceived problems, obstacles, retention factors and support needs of
workers aged 45 years and older8. For workers with a chronic health condition we found
significantly more perceived problems due to ageing as well as obstacles in performing
work tasks and support needs to continue their working life compared to those workers
without a chronic health condition. However, the type of reported problems, obstacles,
retention factors and support needs were divers but very similar in both groups. These
findings suggest that interventions aimed to enhance sustainable employability can be
similar for ageing workers with and without chronic health conditions. Moreover, it
suggests that a preventive intervention to overcome the challenge of an ageing workforce
should be able to deal with individually experienced problems and needs.
A possible strategy that might facilitate ageing workers to deal with these problems,
obstacles, retention factors and support needs is the cognitive‐behavioural process as
described by Meichenbaum and Deffenbacher9 and D’Zurilla and Goldfried10. Both
described a problem‐solving approach by which subjects identify effective or adaptive
solutions for (problematic) situations encountered in the course of everyday living. Based
on these rationales we developed the intervention called ‘Staying healthy at work’ aiming
to enhance the problem‐solving strategies of ageing workers to prolong their working life.
The strategy of the intervention was to change the workers awareness and behaviour by
emphasizing their own decisive role in attaining goals by giving them tools and support
with which they can be effective in carrying out the necessary actions. This may help them
to learn that they can always influence the impact of a situation by: (1) changing the
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situation by themselves; (2) mobilizing the support of others; or (3) accepting the situation
if it proofs to be unchangeable. It contributes to the workers’ belief that they are capable
of solving work‐related problems and attaining goals, and thereby strengthens their self‐
efficacy. In a previous study by Van de Klink et al. the problem‐solving approach was used
in a workers context to facilitate the return‐to‐work of employees on sickness absence
because of mental health problems11. These authors developed and evaluated an
evidence‐based guideline and showed that using the guideline approach shortened sick
leave duration12. In that study the focus was on workers on sick leave with an adjustment
disorder and thus on tertiary prevention. The occupational physician was the appropriate
mediator in facilitating those workers.
The present study is aimed at enhancing sustainable employability of ageing workers
based on individual arrangements, career development activities and aspirations. For this
primary preventive approach the supervisor is the most suitable mediator. Supervisors are
most likely to receive the first indications that accommodations are needed for workers
and are responsible for supporting and facilitating workers13,14. Therefore, supervisors
have been trained in skills to support workers in taking the necessary actions by means of
stimulating self‐direction and enhancing knowledge and competencies.
The aim of the present study was to evaluate the effectiveness of this problem‐solving
based intervention ‘Staying Healthy at Work’ in maintaining and enhancing sustainable
employability compared to usual business. In addition, a process evaluation of the
intervention was performed to explore to which extent the underlying theory and the
program delivery could account for the results.
METHODS
Study design and setting
This study was carried out as a quasi‐experimental trial. Outcomes were measured at
baseline, 3 and 12 months. A process evaluation was performed at the worker’s level at 3
and 9 months. The Medical Ethics Committee of the University Medical Center Groningen
approved the study design, the protocols and the procedures.
Study population and recruitment
The study was performed at the University Medical Center Groningen and the University
of Groningen. Participating departments of the University hospital were paediatric and
intensive care units. Participating departments of the University were technical services,
Effectiveness of the intervention
131
secretarial administrative services, financial economic affairs, human resource advice,
facility services and the library.
Selection of participants in this study was done in a two‐step procedure. First,
eligible supervisors were invited to participate in the trial. Selection of supervisors, and
thereby their workers, took place by the Human Resource Professionals (HRP’s) of the two
organisations. Inclusion criteria for potentially participating departments in this study
were: a) high percentage of workers aged 45 years and older compared to other
departments; b) no other types of intervention studies being performed simultaneously;
and c) no planned re‐organisations. Supervisors at the departments proposed by the HRPs
were invited and informed about the set‐up of the intervention by the researcher prior to
their decision to participate in this study. Those who were first to agree to participate in
this study were allocated to the intervention group until half of the potentially estimated
workers (n=131) were allocated to the intervention group. The remaining supervisors and
their workers formed the usual business group. Supervisors who were willing to
participate in the study received information about the procedure. Recruitment of the
supervisors started in June 2009.
In the second step, eligible workers of supervisors who consented to participate were
asked to participate in this study. Workers were informed about this study by their
supervisor in November 2009. Hereafter, the workers received a letter of invitation to
participate in the study, describing the aim, content and set‐up. Workers on long‐term sick
leave with no prospect of recovery, or workers who were certain to leave the job within
one year were excluded from the study. Participation was voluntarily and workers were
free to leave this study at any time without further consequences. All the workers residing
under a supervisor followed the same treatment regime, i.e. treatment allocation was at
the level of the supervisor. This was done to minimize the probability of contamination15.
The intervention ‘Staying healthy at work’
At the workers‐level the intervention comprised three stages: 1) the workers received a
booklet focused at making an inventory of (work‐related) problems, needs, and career and
personal development opportunities. For these issues the worker was asked to assess the
degree of modifiability; 2) a dialogue between worker and supervisor to discuss solutions
according to a brainstorm format; and 3) making an action plan for the next year follow‐up
period for planning and implementing the solutions. The intervention was incorporated
into the annual appraisal within the organisations.
The intervention provides a booklet for workers to prepare for the appraisal and to
complete their own action plan based on solutions which are chosen and written down by
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132
the workers themselves. Supervisors are responsible for recognizing and rewarding
excellent performance and providing coaching and feedback where needed to improve
performance deficiencies. Also they should ensure that employees have the tools,
resources, and training needed to carry out their responsibilities successfully. Therefore,
supervisors were trained how to challenge the worker to reflect on the feasibility of
solutions and how to present themselves as a source of support for the worker; not by
taking over responsibilities, but by strengthening the autonomy of the worker. The first 2
hours training focused on knowledge regarding sustainable employability, and on
problem‐solving techniques. After 2 weeks the second training (5 hours ) took place,
which consisted of an active training module in which the problem‐solving techniques
were practiced by role‐play with an actor.
Business as usual
Workers in the usual business group received their regular annual appraisal.
Primary outcome variables
Work ability was assessed with the Work Ability Index (WAI), which covers seven aspects,
each of which is evaluated with one or more questions16. The WAI is a reliable and valid
standardized measure of work ability17. Scores range from 7 to 49; higher scores indicate
better work ability.
Vitality was measured with the single item vitality scale of the 12‐Item Short Form Health
Survey (SF12) and its reliability and validity have been documented18,19. The item scores
were ‘never’, ‘seldom’, ‘sometimes’, ‘mostly’, and ‘always’.
Productivity was measured with the quantity scale of the Quality and Quantity (QQ)
method measuring productivity loss at work20. The QQ provides a reliable and valid tool
for measuring quantity and quality of work on a daily basis. Workers were asked to
indicate how much work they had performed during regular hours on their last regular
workday as compared with normal. The quantity of productivity was measured on a scale
from 0 (nothing) to 10 (regular quantity)3. The outcome was dichotomised into
productivity loss (scoring 0‐9) and no productivity loss (scoring 10). The quality of
productivity was not measured because the quality and quantity question are highly
correlated3.
Effectiveness of the intervention
133
Secondary outcome variables
Secondary outcomes were assessed at baseline and at 12 months follow‐up. Fatigue was
assessed with the 8 item subscale ‘the subjective feeling of fatigue’ of the Checklist
Individual Strength (CIS)21. The items were scored on a 7‐point Likert scale ranging from
‘Yes, that is true’ to ‘No, that is not true’. Scores were summed leading to possible scores
ranging between 8‐56; higher scores indicate higher degrees of fatigue. Psychosocial work
characteristics were measured with the Job Content Questionnaire (JCQ)22. The JCQ
consists of five subscales: job demands (5 items, range 12‐48), decision authority (3 items,
range 12‐48), skill discretion (6 items, range 12‐48), social support from supervisors (4
items, range 4‐16) and co‐worker support (4 items, range 4‐16). Each item was rated on a
4‐point scale from ‘strongly disagree’ to ‘strongly agree’.
Perceived work attitude was measured with the Dutch Language version of the Work
Involvement Scale (WIS‐DLV), which covers 6 items on a 4 point scale (strongly disagree to
strongly agree). Higher scores (range 0‐100) indicate more positive attitudes towards
work23. Self‐efficacy was measured with the standardized Dutch version of the General
Self‐Efficacy Scale (ALCOS‐16)24, which assesses the subjects’ expectations of their general
capacities25. The instrument consists of 16 items assessing the subscales ‘willingness to
exert effort in completing the behaviour’ (range 6‐30), ‘persistence in the face of
adversity’ (range 6‐30), and ‘willingness to initiate behaviour’ (range 4‐24). The five
answering categories range from ‘strongly disagree’ to ‘strongly agree’; a higher score on
this questionnaire indicates higher self‐efficacy. Work engagement was measured with the
short Dutch version of the Utrecht Work Engagement Scale (UWES‐9)26. The nine items
reflect three subscales covering the underlying dimensions of engagement. These
subscales vigour, dedication and absorption (each subscale 3 items) are scored on a 7‐
point frequency rating scale ranging from ‘never (0)’ to ‘always/ever’ (6).
Potential confounders
At baseline, data on potential confounders at the level of the workers was assessed by
questionnaire including age, gender (male/female), education (low = lower vocational
education/ medium = intermediate secondary or vocational education/ high = higher
vocational education and university), occupation (executive/ secretarial or administrative/
policy/ management), sector (health care/ education), shift work (yes/ no), duration of
current position and years paid work (0‐10/ 11‐20/ 21‐30/ 31‐40/ >40years).
Chapter 7
134
Process evaluation at the workers level
The process evaluation was carried out by using a questionnaire at the worker’s level to
measure whether the intervention was carried out as intended. To what extent all
intended intervention components were performed was collected with registration forms
by the supervisor (e.g. appointment dialogue and performing dialogue) and by the
researchers (e.g. preparing for the dialogue with first step of the booklet, to draw up an
action plan, and performing described action(s)). Workers in the intervention group were
asked (yes/no) to evaluate the content and the relevance of the information leaflets they
received in order to prepare for the dialogue, to what extent they experienced support
from the booklet and whether the focus on the modifiability of situations motivated them
to plan and implement solutions. The quality of the dialogue (rated on a 5‐point scale from
excellent to very poor), the duration of the dialogue (in minutes) and the support they
experienced from the supervisor were assessed.
Statistical analysis
All statistical analyses were carried out at the workers’ level and according to the
intention‐to‐treat principle. The chi‐square test (ordinal and nominal variables) or t‐test
(mean scores) were used to compare differences on baseline characteristics between the
intervention and usual business group. For the primary outcomes, we performed linear
(work ability), ordinal (vitality), and logistic (productivity) multilevel analyses. We had
planned to incorporate three levels (supervisor, worker, observation) in all models.
However, random coefficients at the supervisor level did not improve model fit. Thus, two
levels (worker and observation) were incorporated in the models. We tested for
interactions between the intervention and time to follow‐up by incorporating interaction
terms in all multilevel analyses. For the secondary outcomes we performed linear
regression analyses. All analyses included adjustment for baseline levels of the outcome,
baseline levels of the other primary and secondary outcomes and for the potential
confounders. A detailed description of the sample size analyses has been provided
elsewhere27. The multilevel analyses were performed with MLWin version 2.24. Linear
regression analyses were carried out with the Statistical Package SPSS version 18.0 (SPSS
Inc. Released 2009, Chicago: SPSS Inc). For all analyses a two‐tailed p‐level of <.05 was
considered to indicate statistical significance.
Effectiveness of the intervention
135
RESULTS
During the recruitment period 28 supervisors were approached to participate in this study.
Nine supervisors declined for reasons such as upcoming reorganisation and time pressure.
The remaining 19 supervisors were allocated in either the intervention (n=12) or usual
business group (n=7). Following the allocation of the supervisors, the total of 236 workers
were divided to the intervention group (n = 129) or usual business group (n = 107). An
overview of the recruitment flow is presented in Figure 1.
136
Figure 1: Flow diagram
of the participants through
the phases of the trial
Effectiveness of the intervention
137
Non‐participation and loss to follow‐up
Workers who did not meet the inclusion criteria were excluded from this study (n=16). The
most common reasons for exclusion were sick leave for longer than 1 year (n=10) and
upcoming pension (n=6). In the intervention group, 3 workers refused to participate, and 9
worker did not participate due to unknown reasons. In the usual practise group, 36
workers did not participate in this study because they refusal to participate (n=5) or due to
unknown reasons (n=31). There was no data on demographic or work related outcomes of
these workers to compare them with workers participating in this study.
During the intervention, 2 supervisors in the intervention group were unable to
implement the intervention because of unforeseen reorganisation of the department for
one of the supervisors and long‐term sickness of the other supervisor. Therefore, we lost
26 workers in the intervention group after the baseline measure. For the remaining
workers, data of both follow‐up measures was missing for 18 and 5 workers in the
intervention and usual business group respectively. These 49 workers who were lost after
baseline had a lower educational level (p =.003), were more fatigued (p =.008) and
reported lower scores on vitality (p=.004), and on the self‐efficacy scales willingness to
exert effort in completing a behaviour (p =.007) and willingness to initiate behaviour
(p=.026). Data of 125 workers was available for the analyses; 64 workers in the
intervention group and 61 workers in the usual business group respectively. Of these
there was no data for 12 workers at T1 (intervention group n=9; usual practise n=3) and 13
workers at T2 (intervention group n=5; usual practise n=8).
Chapter 7
138
Table 1: Baseline characteristics of the total population, intervention group and usual business group
All workers Intervention
group
Usual business
group
Characteristics N % N % N %
Age in years (mean, SD) 123 52.4 (5.3) 52.8 (5.6) 51.9 (4.8)
Gender (n=145)
Female 117 81 58 73 59 89
Male 28 19 21 27 7 11
Education (n=145)
Low 21 14 12 15 9 14
Medium 61 41 30 38 31 48
High 63 43 38 47 25 38
Occupation (n=146)
Executive 106 72 66 83 40 61
Secretarial or administrative 26 18 7 9 19 29
Policy 9 6 6 7 3 4
Management 5 4 1 1 4 6
Sector (n=148)
Health care 106 72 64 78 42 64
Education 42 28 18 22 24 36
Shift work (n=145)
Yes 89 61 59 75 30 45
No 56 39 20 25 36 55
Duration current position in years (n=144)
0‐10 27 19 15 19 12 19
11‐20 30 21 15 19 15 23
21‐30 46 32 28 35 18 28
31‐40 36 25 21 26 15 23
>40 5 3 1 1 4 7
Years paid work (n=145)
0‐10 1 1 1 1 ‐‐ ‐‐
11‐20 20 14 11 14 9 14
21‐30 53 36 28 35 25 38
31‐40 62 43 37 47 25 38
>40 9 6 2 3 7 10
Effectiveness of the intervention
139
Baseline Characteristics
The baseline characteristics of the workers in the intervention and usual business group
are presented in Table 1. Significant differences at baseline between the intervention and
usual practise were found on gender, occupation and shift work. The intervention group
consisted of higher percentages males (27% vs. 11%; p=.015), more executive workers
(83% vs. 61%) and less secretarial workers (9% vs. 29%; p=.005), and more shift workers
(75% vs. 45%; p=.001) compared to the usual business group. Table 2 shows the
frequencies and mean scores of the outcome variables at baseline and follow‐up
measurements. No significant differences were found on baseline between the
intervention and usual business group, except for the scale job demands, which showed a
small difference (32.86 vs. 32.07; p=.004).
Primary and secondary outcome measures
The results regarding effectiveness of the intervention with respect to the primary and
secondary outcome measures are presented in Table 3. A significant adverse effect during
follow‐up was found for work ability (B=‐1.33, 95%CI ‐2.45 to ‐0.20) and vitality (OR=0.10,
95%CI 0.02‐0.46). This means that workers in the intervention group had a 1.33 points
lower mean score on the WAI than workers in the control group and that they had a 0.10
times higher odds of being in a higher vitality category than the persons in the control
group. We found no statistically significant difference between both groups on
productivity. No interaction effects between the intervention and time to follow‐up for
any of the primary outcomes were found. Positive significant results in favour of the
intervention group were found for the secondary outcomes work attitude (B = 5.29, 95%CI
‐9.59 to ‐0.99), self‐efficacy (persistence subscale) (B = 1.45, 95%CI 0.43‐2.48) and the
subscale skill discretion of the job content questionnaire (B = 1.78, 95%CI 0.74‐2.83).
140
Table 2: Percentages and m
eans of the primary and secondary outcomes at baseline, 3 and 12 m
onths
Intervention group
Usual business group
Baselin
e3 m
onths
12 m
onths
Baselin
e3 m
onths
12 m
onths
N = 82
N = 55
N = 59
N = 66
N = 58
N = 53
Primary outcomes
Work ability (mean, SD)
39.0
5.4
38.9
5.3
38.7
5.2
38.9
5.4
38.9
5.1
38.9
4.7
Poor (%
)7
4
46
02
Moderate (%)
21
22
22
22
31
23
Good (%)
50
55
56
52
51
58
Excellent (%
)22
18
18
20
18
17
Vitality
Never (%)
00
0
00
0
Seldom (%)
32
2
23
0
Sometim
es (%)
18
20
20
16
16
25
Mostly (%)
74
70
73
79
71
68
Always (%)
67
5
310
8
No productivity loss (%)
66
76
61
67
76
64
Secondary outcomes
Mean
SDMean
SD
Mean
SDMean
SDMean
SDMean
SD
Perceived fatigue
18.89
9.4
19.53
10.4
19.58
10.7
21.55
11.4
Job content
Job dem
ands
32.07
4.9
31.71
5.4
32.86
6.8
31.15
5.5
Decision authority
33.90
6.0
34.37
5.9
35.64
7.1
34.94
7.4
Skill discretion
38.63
4.4
38.31
4.0
38.15
5.1
37.21
4.4
141
Table 2 continued
Intervention group
Usual business group
Baselin
e3 m
onths
12 m
onths
Baselin
e3 m
onths
12 m
onths
Secondary outcomes
Mean
SDMean
SD
Mean
SDMean
SDMean
SDMean
SD
Support from supervisor
10.84
2.2
10.61
2.1
11.68
2.3
11.71
2.7
Co‐w
orker support
12.20
2.1
12.22
1.5
12.71
1.8
12.70
1.5
Perceived work attitude
28.75
15.3
27.49
13.5
29.55
15.1
30.50
15.0
Self‐efficacy
67.13
6.9
65.85
6.1
66.30
8.9
64.70
10.5
Willingness to exert effort in
completing the beh
aviour
25.88
3.5
25.11
3.2
25.47
3.6
24.58
4.4
Persisten
ce in
the face of
adversity
25.24
2.9
25.24
2.9
24.89
3.6
24.79
3.7
Willingness to initiate beh
aviour
16.01
2.8
15.48
2.8
15.94
3.2
15.34
3.4
Work engagemen
t total
4.34
0.9
4.50
0.9
4.29
1.1
4.44
0.8
Vigour
4.49
0.9
4.55
1.0
4.46
1.0
4.62
0.9
Ded
ication
4.65
1.0
4.84
0.9
4.69
1.2
4.77
1.0
Absorption
3.89
1.2
4.11
1.1
3.73
1.2
3.94
0.9
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142
Table 3: Results of the regression analyses to measure the of the intervention on primary and secondary outcomes
Outcome measure* B OR p‐value 95%CI
Lower Upper
Primary outcomes+
Work ability ‐1.33 0.021 ‐2.45 ‐0.20
Vitality 0.10 0.003 0.02 0.46
Productivity 0.83 0.779 0.23 3.00
Secondary outcomes
Perceived fatigue ‐0.11 0.935 ‐2.83 2.61
Job content
Job demands ‐0.82 0.344 ‐2.53 0.89
Decision authority ‐0.55 0.557 ‐2.38 1.29
Skill discretion 1.78 0.001 0.74 2.83
Support from supervisor 0.17 0.659 ‐0.59 0.94
Co‐worker support 0.03 0.906 ‐0.41 0.46
Perceived work attitude 5.29 0.016 ‐9.59 ‐0.99
Self‐efficacy
Willingness to exert effort in
completing the behaviour 0.11 0.84 ‐0.95 1.17
Persistence in the face of
adversity 1.45 0.006 0.43 2.48
Willingness to initiate behaviour ‐0.47 0.288 ‐1.33 0.40
Work engagement
Vigour ‐0.21 0.118 ‐0.47 0.05
Dedication ‐0.03 0.846 ‐0.31 0.25
Absorption ‐0.07 0.692 ‐0.40 0.26
* Analyses on outcome measures were adjusted for age, gender, education, occupation, sector, shift work, duration current position and years paid work + Primary outcomes were analysed with linear (work ability), logistic (productivity) and ordinal (vitality) multilevel analyses
Effectiveness of the intervention
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Process evaluation
Of the workers in the intervention group, 54 (66%) filled out the process evaluation
questionnaire after 3 months. The first step of the intervention (inventory and
modifiability) was performed by 91% (n=49) of the workers. The dialogue took place
within 3 months after the baseline measurement for 52 (96%) workers. Preparation of the
action plan in the third step of the intervention was performed by 29 workers (56%); 27 of
these workers received feedback of their supervisor. Satisfaction with the content and
relevance of the information, leaflets and booklet of the intervention was reported by 53
workers (96%). The first step of the intervention supported 32 workers (65%) to formulate
opportunities for personal development, career opportunities and experienced problems
in the work situation. Specifying the modifiability motivated 31 workers (63%) to plan
actions. The average time of the dialogue was 38 minutes (range 5‐60 minutes) and the
communication between workers and supervisor was generally good (n=32; 62%) to very
good (n=17; 32%). Three workers required a follow‐up meeting with the supervisor.
After 3 months 43% of the workers (n=23) reported that the intervention had increased
their ability to clarify and explore problems with work participation and career aspiration.
About half of the workers reported to have become more capable in conducting a
dialogue with the supervisor about sustainable work participation (n=25; 46%) and to set
up a structured action plan to improve work conditions after the intervention (n=23; 43%).
Fifty‐four per cent (n=29) of the workers stated that the intervention had made them
aware of the responsibility to create a healthy workplace. The intervention contributed to
more self‐confidence in changing the work situation for 37% (n=20) of the workers and to
enhanced skills to discuss work performance with the supervisor for 35% (n=19). To a
lesser extent, the intervention resulted in better functioning at work (n=8; 15%) and more
pleasure in the work situation (n=10; 19%). The same trends were observed after nine
months (Table 4).
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Table 4: Results of the process evaluation at workers’ level after 3 and 9 months
After 3 months
(n=54)
After 9 months
(n=50)
n % n %
The intervention has increased my ability to:
…clarify and explore problems with work
participation and career aspirations
23 43 19 38
…establish a dialogue with the supervisor about
sustainable work participation
25 46 24 48
…set up a structured plan to improve the work
conditions
23 43 19 38
…perform my work as before 13 24 7 14
Through the intervention I am:
…more aware of the responsibility to create a
healthy and motivating work place
29 54 28 56
…functioning better at work 8 15 7 14
…taking more actions to improve the work
conditions
23 43 17 34
The intervention contributed to:
…more pleasure in the work situation 10 19 8 16
…more self‐confidence to accomplish changes in
the work situation
20 37 14 28
…better skills to discuss work functioning with the
supervisor
19 35 13 26
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145
DISCUSSION
The problem‐solving intervention ‘Staying healthy at Work’ designed for workers to
enhance sustainable employability showed no superior effect on productivity and a
negative effect on work ability and vitality compared to usual business. However, positive
effects were found on the secondary outcome measures perceived work attitude, the self‐
efficacy subscale persistence in the face of adversity and the subscale skill discretion of
the psychosocial work characteristics.
To our knowledge this study is the first prospective controlled trial aimed to support
sustainable employability of ageing workers by means of an intervention focussing on
enhancing the problem‐solving capacity of workers. Most intervention studies aimed at
promoting and enhancing the participation in working life of workers, provide a lifestyle
training programme to improve job retention, increase vitality or to decrease work
disability28‐30. This study provides workers a guidance how to prolong work participation in
good health by enhancing the workers’ awareness and behaviour by emphasizing their
own decisive role in attaining goals and carrying out the necessary actions. As the labour
participation of specifically ageing workers need to be extended, the results of this study
are innovative and provide valuable information for (occupational) health researchers,
policy makers and employers. The fact that we found no or negative effects on the
primary health‐related outcomes is in line with earlier studies focussing on work‐site
interventions to support sustainable employability31,32. We have used the theoretical
model of Kristensen to discuss our results33.
Based on the results of previous problem‐solving intervention studies we presume that
our negative findings on the primary outcomes variables do not result from theory failure.
These studies showed that problem‐solving intervention studies on work related
outcomes had a superior effect on sickness absence12, return to work12,34, prevention of
depression35, and treatment of anxiety disorders36. Moreover, it is also shown that a
problem‐solving training in the workplace can increase problem‐solving skills and
problem‐solving self‐efficacy in the course of improving positive affect, job satisfaction,
and life satisfaction37. Therefore, our assumption that a self‐directed cognitive behavioural
intervention enhanced the problem‐solving capacity of ageing workers towards
sustainable employability might be effective is still valid. In our study, the positive results
on the secondary outcomes work attitude, persistence in the face of adversity and skill
discretion acknowledge that the intervention changed the awareness and behaviour of
workers to enhance work participation. In addition, the process evaluation on the
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workers’ level confirms this. Therefore, we assume that lack of impact of the intervention
on the primary outcome measures must be explained by program failures of the
intervention33. We will elaborate on both aspects of program failure: dose delivered and
dose received.
On the level of dose delivered the short duration of the training of the supervisors might
explain the lack of the effectiveness of the intervention on the primary outcome
measures. Knowledge and basic skills in communication of the supervisors was low and,
during the training, a lot of time was spent on these basic skills instead of the problem‐
solving approach. Moreover, the duration and frequency of the training for supervisors
(two sessions of two and five hours respectively) might have been too short to transfer
the acquired skills into attitude and practice. Prior to the implementation, the research
team suggested to train the supervisors for two days or three training sessions to
accomplish the targeted level of knowledge and skills necessary to perform the
intervention. However, the intervention was conducted as part of the normal activities of
an organisation and thereby time of the supervisors to participate in the study was
limited. At the organisational level they were convinced that their supervisors were
trained well and the supervisors’ skills were in line with the skills necessary to perform the
dialogue. Therefore, we had to deal with restrictions in time investment of the
supervisor’s during implementation of the training.
On the workers’ level (dose received), defining a structured action plan after the dialogue
was not carried out by 44% of the participants. This low adherence might have
contributed to the low effectiveness of the intervention. Reasons for not defining an
action plan were that workers did not have the ability to translate the points discussed
during the dialogue into appropriate actions, high work pressure, lack of knowledge about
available interventions in the organisation or lack of motivation. In contrast, the first step
of the intervention was performed by almost all workers. This discrepancy in adherence
between parts of the intervention might also partly explain our findings. The first step
makes workers aware of their own responsibility, obstacles, retention factors and needs
towards sustainable employability. As a consequence, workers can experience (emotional)
feelings of increased (work) load and decreased work ability. The more positive
experiences and effects result from the next, solution focused, steps of the intervention.
These steps were not taken by many workers and, if taken, their effect appears later. The
positive results on the secondary outcomes in our study imply that the intervention
changed the perspectives of workers about awareness and responsibility of sustainable
employability in a positive way. These results are in line with results of other behavioural
Effectiveness of the intervention
147
intervention studies, that have shown that cognitive behavioural interventions improve
self‐efficacy, job satisfaction and motivation towards return to work28,38 and coping with
chronic conditions39,40. In our intervention, workers understood their own responsibility
towards a healthy and sustainable working life, but missed the optimal benefit of the later
steps of the intervention. Therefore we assume that the intervention might be effective in
the long term on enhancing sustainable employability if program failures are avoided.
In addition to the time frame of the intervention, which is discussed above in relation to
program failures, the non‐randomised design might have caused bias. The earlier the
supervisor agreed to participate, the more likely it was that he/she was allocated in the
intervention group. The departments in the intervention group were comparable to the
control group, because the departments which were asked to participate in the study
were matched on percentage of ageing workers and comparable job tasks to overcome
this source of bias in the study design. However, it might be possible that especially
cooperative and committed supervisors, who already put a lot of effort in sustainable
employability of their ageing workers, were allocated to the intervention. Contamination
between supervisors in the control and intervention group cannot be excluded. Although
we applied cluster randomisation to avoid contamination between workers, supervisors
from both groups might have had common activities inside the organisation and could
have discussed the study. Furthermore, there was a small difference between the
intervention and the usual business group at baseline for the secondary outcome measure
job demands. However, this and other differences between both groups were taken into
account in the analyses.
Despite of the above mentioned shortcomings, there also were some successful elements
in our intervention study. The results suggest that workers in the intervention group were
better able to identify or discover effective solutions for specific problem encountered in
working life compared to workers in the usual business group who received an annual
appraisal. Although both groups of workers receive an annual appraisal, the results shows
that the intervention activates workers to be aware of their own responsibility for actions
towards a healthy and motivating work place. This is in line with experiences of the
management of the participating organisations, because in practice most workers feel
they are being judged and marked on performance. Workers do not discuss what they
enjoy doing, where they have difficulties, aspirations and opportunities because they
don’t know how to prepare beforehand. Moreover, the intervention had the strength of
an integrated approach which provides close collaboration between the worker and
supervisor as well as human research management that ensures that employees have the
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tools, resources, training, and development needed to carry out their responsibilities
successfully. Earlier research has shown that a more participatory and supportive
approach of the supervisor might help workers to identify their challenges and implement
solutions41. The close cooperation with the human resource professionals during the
implementation ensured that the intervention was in line with the existing organisational
policy. However, during implementation it is important to take into account the fidelity
(delivering the intervention as planned), because non‐fidelity will dilute the difference
between the intervention and control group. An additional asset of the intervention is that
the method can be incorporated into the cycle of annual appraisal between worker and
supervisor within the organisations.
Future research of intervention studies at workplaces based on an integrated problem‐
solving approach needs to be done with strict program integrity to establish whether or
not such an intervention is effective in increasing sustainable employability. What is now
needed is a randomized controlled trial including a detailed process evaluation on both
workers and supervisors level to evaluate the effectiveness of the intervention. Program
failures might be prevented by a) development of a monitoring system to support the
setup of a structured plan after the dialogue with specific, well‐defined and realistic goals
and to perform the actions and solutions described in this plan, and b) telephone support
and the organisation of peer groups for supervisors during the intervention period to
improve their (communication) skills and supportive role based on the problem‐solving
approach. In addition, information about the quality of the annual appraisal and the
received support of the supervisors in the control group could show to what extent the
intervention contributes to a healthy working life compared to the traditional appraisal. If
the intervention is proven effective, it is important to investigate the usability and
effectiveness of the intervention in different occupational groups.
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149
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8
General discussion
General discussion
155
The main objectives of this thesis were to provide insight into the needs and determinants
regarding a sustainable working life by conducting a survey study, and to develop and
evaluate an intervention aimed to enhance sustainable employability among workers aged
45 years and older, with and without a chronic health condition. This final chapter
presents and discusses the main findings in the light of those objectives, and also
discusses the methodological implications and recommendations for future use of the
intervention, and for policy and practice.
MAIN FINDINGS AND INTERPRETATION
Problems experienced, obstacles, retention factors and needs
In our sample, 42% of workers aged 45 years and older experienced problems due to
ageing. About a quarter of those workers (26%) reported obstacles to performing their
work. Retention factors were reported by 82% of the workers, and 38% reported that they
had special support needs if they were to continue working over the coming years.
Problems due to ageing were especially related to decreased physiological and
psychological functioning, for example, energy level, sustainable attention, recall memory,
visual acuity, physical condition and muscle strength functions. Perceived support needs
concerned work‐related environmental factors in particular, for example, working fewer
hours, task reduction, reducing time pressure and improvement of the physical conditions
in the work place (chapter 2). Our results showed that ageing is a challenge for a lot of
workers from the age of 45 years onwards during working life, which implies the
importance of attention to retention factors and needs for maintaining and increasing
sustainable employability.
Determinants of work ability
The results of our cross‐sectional survey showed significant associations between some
individual characteristics, work conditions, psychosocial factors and work ability. Older
age, the presence of a chronic health condition, lower education, executive work, and
physically demanding jobs were associated with a lower work ability level (chapter 4). We
used the single‐item work ability score to determine these factors in a sample of workers
aged 45 years and older working in different occupations and organizations for the current
work ability compared with the lifetime best. Our findings were comparable with several
previous prospective cohort and cross‐sectional studies that used the total work ability
score1‐7, which contains many questions that only indirectly measure work ability (e.g. sick
leave taken during the past year, mental resources and vitality)8. Those studies were often
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performed in a specific group of the working population such as municipal workers and
home care workers2,9.
Furthermore, we found that an active coping style is positively associated with work ability
and this association is not influenced by higher levels of job control or instrumental
support. We found negative associations between both emotional and avoidance coping
styles and work ability, but found no interaction effects of emotional support on those
negative associations (chapter 5). To our knowledge, this is the first published study that
examines the relationship between coping styles and work ability level.
Different types of ageing
In this thesis the target group was workers aged 45 years and older. By reason of research
we had to set an age criterion in agreement with other studies7,10‐12, although we realise
that any specific age is arbitrary and cannot be regarded to be a watershed in itself in
terms of defining who is old and who is not. Whereas ageing refers to many changes in
biological, psychosocial and social functioning over time13‐17 and is not simply an effect of
time (i.e. one’s chronological or calendar age), we focused also on other types of ageing
like functional ageing (chapter 3). We operationalized functional ageing in terms of
outcomes of health status, that is, the presence of a chronic health condition (yes/no) and
perceived health, measured with subscales of the SF‐36.
More than one third of the workers in our study population (37%) reported the presence
of a chronic health condition (chapter 3), which is consistent with previous findings in the
Dutch working population18,19. Workers with a chronic health condition scored lower on
the perceived health subscales compared to workers without a chronic health condition
(chapter 4). Univariate analyses showed that lower scores on measures of perceived
health status were associated with more commonly experienced problems, greater
numbers of obstacles, more support needs, fewer experienced retention factors and less
chance on a good or excellent work ability score (chapter 3). Moreover, the measures of
perceived health status were strongly related to the presence of a chronic health
condition and largely explained its association with work ability (chapter 4). This is
reasonable because the subscales of the perceived health questionnaire (SF‐36) are multi‐
item scales which assess distinct aspects of health and can better determine health status
than a single‐item dichotomous question about the presence of a chronic health condition
(yes/no). Other studies have shown that perceived health problems contribute to an early
exit from the labour market20‐24.
General discussion
157
As well as chronological and functional age, Kooij et al. also defined psychosocial and
organizational age25. The former concerns how old an individual feels, looks and acts, and
how old the person desires to be. The most common reason for starting to feel older was
change in health26,27 and previous results indicated that especially feeling old relative to
one’s chronological age was positively associated with several indicators of job‐related
strain across several countries28. Organizational age refers to the aging of individuals in
jobs and organizations25. Changing jobs gives you a broader base of experience and a more
varied background creates a greater demand for your skills. Depth of experience means
that workers’ are more valuable to a larger number of employers which increase their
sustainable employability. In this thesis we did not examine the relation between
psychosocial, organizational and chronological age. Although these different
conceptualizations of age are often interrelated. They might have distinct effects on work‐
related attitudes25. Therefore, it is sufficient to note here that future research requires
paying attention to different conceptualizations of ageing with regard to sustainable
employability.
Stratified analyses of older workers with and without a chronic health condition showed
no substantial differences in psychosocial factors and work conditions associated with
work ability (chapter 4). However, the explained variance in work ability score was 42.8%
for workers with a chronic health condition, compared to 28.7% for workers without a
chronic health condition. These findings suggest that workers with a chronic health
condition might benefit the most from a policy focusing on enhancing the associated
variables.
The association between active coping and work ability was stronger for workers with a
chronic health condition than for workers without a chronic health condition, and this
association was strengthened by job control (chapter 5). This is consistent with previous
studies which found that people with a moderate to high impairment in physical function
and emotional well‐being reported more frequent use of active coping strategies29. For
example, a longer duration of chronic fatigue syndrome resulted in the greater use of an
active coping approach30. This suggest that the health condition provides an additional,
partly controllable challenge to adapt to work demands. A strong focus on an active
coping style might almost be a prerequisite to enhance ability in controllable situations.
Development of an intervention
The findings of our survey study showed that the determinants of sustainable
employment were related to the worker’s individual situation (e.g. presence of chronic
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health condition, problems, needs, occupation, coping style). Based on the workers’
responses we found that, in particular, individual adjustments to the work situation are
needed to enhance sustainable employability, such as task reduction, reducing time
pressure, improvement of the physical conditions in the work place and ergonomic
adjustments (chapter 2). In addition, workers become increasingly responsible for their
own career in the last decade due to changes in the labour market. Workers need to be
aware of their own responsibility and decisive role in creating and maintaining a healthy
work life. Therefore, we expected that a tailored approach would be necessary to enhance
sustainable employability.
Since individual accommodation to the work situation should be coordinated with a
supervisor, an intervention to increase sustainable employability should emphasize good
cooperation between the worker and supervisor. Supervisors are most likely to see the
first indications that individual accommodation is required31,32. It has been shown that a
more participatory and supportive approach by the supervisor might help workers to
identify the challenges and implement solutions to increase job performance33,34.
Furthermore, for employers, it is important that an intervention designed to increase
sustainable employability accords with existing practice, policy and available tools in the
organization. Therefore, our intervention was incorporated into the annual appraisal.
Based on these findings, we developed an intervention called ‘Staying Healthy at Work’.
Our intervention offers a tailored approach to enhance sustainable employability, by
increasing the workers’ resources and their ability to continue working until retirement, in
good health. (chapter 6). The intervention is based on encouraging a self‐directed
cognitive behavioural process that will enhance the workers’ problem‐solving capacity,
and entails a partnership between the employer and worker, ultimately aiming to increase
the problem‐solving capacity of both worker and supervisor. Although this should involve
support from others, the workers themselves are mainly responsible for the actions
required and for implementing the solutions.
The purpose of our intervention was to increase the workers’ awareness and change their
behaviour by emphasizing their own decisive role in attaining goals, giving them tools and
support with which they could be effective in carrying out the necessary actions. This is in
line with our finding that adapting an active coping style is an effective way to increase
work ability (chapter 5). The first stage of the intervention is the key component. Workers
create an inventory of work‐related problems, needs and career and personal
development opportunities. To help them to discover that they can influence the impact
General discussion
159
of a situation they were invited to rate the ‘influenceability’ of the situation in one of the
three categories: (1) changing the situation themselves, (2) mobilizing the support of
others or (3) by accepting the situation if it proves to be unchangeable. This contributes to
the worker’s belief that they are capable of solving work‐related problems and attaining
goals, and thereby strengthens their self‐efficacy. In the second stage, possible solutions
are discussed with the supervisor, while in the third stage workers set up an action plan
and implement the solutions. We expect that the intervention will make workers aware of
the opportunities and their own responsibility to prolong their working life and remain
employed in good health.
Evaluation of the intervention
The intervention ‘Staying Healthy at Work’ was evaluated in a quasi‐experimental trial
(n = 125), among nurses (paediatric and intensive care units) and university employees
(technical services, secretarial administrative services, financial affairs, human resource
advice, facility services, and the library). The intervention was implemented as intended
and participation was voluntary.
The intervention had no effect on productivity and a small but negative effect on work
ability and vitality (chapter 7). Additional analyses of the secondary outcomes showed that
work attitude, self‐efficacy and skill discretion increased significantly in the intervention
group compared to the control group. After 12 months, the intervention had contributed
to an increased awareness among more than half of the workers concerning their own
responsibility to create a healthy and stimulating workplace. In addition, 40% of the
workers improved in their ability to conduct a dialogue with their supervisor about
sustainable work participation and setting up a structured action plan.
Explanations for the lack of effect on the primary outcomes can be found on different
stages of the intervention. On the workers’ level, we found a discrepancy in adherence
between the first stage of the intervention (inventory and dialogue) and the third stage
(the action plan). While the first two steps of the intervention make workers more aware
of their problems, the opportunities, needs and personal responsibility to lead a healthy
and motivated working life, they do not provide the positive emotional impetus required
to take the final step. Therefore, the workers might have missed out on the optimal
benefit of the intervention. A monitoring system to support the setup of a structured plan
after the dialogue, with well‐defined actions and solutions to enhance sustainable
employability, might increase workers’ adherence.
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On the level of the supervisors, the amount of time available to train the supervisors in a
problem‐solving approach and develop the required skills might have been too short to
transfer the acquired skills into practice. Supervisors were found to be unaware of how to
present themselves as sources of support, concerned with the problems experienced by
workers. Because the implementation of the intervention occurred during working time,
the number and total length of training sessions for supervisors was limited to a first
session of two hours and a second session of five hours. Role play with an actor, used
during the supervisors’ training session, focused on improving the skills of supervisors in
encouraging workers to assume greater responsibility for their actions in order to enhance
sustainable employability. This focus indicates that supervisors often take over the
responsibility to find solutions, which may be counter‐productive. In future, it might be
helpful to support the supervisors by using peer‐group sessions during the intervention
period to improve their communication and other relevant skills. This supportive role
might compensate for the problems associated with the short period of time available for
training.
Another reason which might explain why we did not find a positive effect on the primary
outcomes could be the short follow‐up. Implementation of the intervention makes
workers aware of their own responsibility, the obstacles, retention factors and needs
regarding sustainable employability. As a consequence, workers can experience feelings
associated with increased work load and decreased work ability. The third stage of the
intervention provides a strategy to change the situation, but the workers need time to
commence the action and transform their work situation or personal attitude step by step.
It might be the case that performing and integrating the solutions in the workplace takes
some time.
It is also plausible that we did not find an effect because supervisors were already
concerned about sustainable employability. We cannot rule out that supervisors in the
usual business group and control group also paid attention to the sustainable
employability of their workers.
In addition, people aged 45 years and older who are still working might be a select,
relatively healthy group of the general population of this age. This phenomenon refers to
a healthy worker effect, which is often encountered in occupational situations 35,36. In our
cohort, the healthy worker selection is probably stronger than in the current population of
ageing workers. The healthy worker effect might lead to an underestimation of the
existing impact of ageing on work participation. Moreover, while participation in the study
General discussion
161
was voluntary, it is possible that healthy workers who already put a lot of effort into
sustainable employability were more likely to choose to participate.
The positive results on the secondary outcomes in our study imply that the intervention
positively influenced the perspectives of workers concerning their awareness and of
feeling responsible for sustainable employability. These results are in line with those of
other intervention studies on behaviour37‐39 and coping with chronic conditions40,41. In
those studies the cognitive behavioural interventions change the workers’ attitude and job
satisfaction, which has potential impacts on work performance and product quality. For
example, by focusing more and earlier on work‐related aspects and return to work for
workers with common mental disorders the functional recovery in work substantially
speeded up. Moreover, cognitive behavioural interventions have become common
successful alternatives to traditional medical and active rehabilitation approaches for
workers with low back pain.
METHODOLOGICAL CONSIDERATION
The study is based on a considerable sample size of workers who undertook various
occupational activities (e.g. physical work, back office, health care, teaching and cleaning)
and were employed in different organizations. A mixed method approach was used, which
means that quantitative and qualitative research complemented each other, providing
insight into the workers’ views and experience of ageing problems and the determinants
and adaptation strategies associated with work ability. It provided an extended insight
into how to enhance sustainable employability and the differences between workers with
and without a chronic health condition.
To our knowledge this is one of the first intervention studies that evaluated a worksite
intervention consisting of a strategy aimed to promote the problem‐solving capacity of
ageing workers and, in turn, sustainable employability. As prolonging working life is
important in today’s society, the outcomes of this study are therefore not only innovative
but also provide valuable information. However, some methodological issues should be
taken into consideration about the survey study, intervention study and measurements.
Survey study
Design
The cross‐sectional design of the survey study did not permit exploration of causal
relationships between the associations we found. Nevertheless, the results are still of
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interest, as they provide an initial insight into factors that are important for interventions
on work ability among workers aged 45 years and older, with and without a chronic health
condition.
Response rate
The overall response rate of 36% for the survey study was considered to be satisfactory
and is regarded to be reasonable for anonymous survey studies in the Dutch working
population 42. As participation in the survey was voluntary and no information was
available about the non‐respondents, result biases related to selective participation
cannot be ruled out. However, there is no reason to expect that workers with problems
returned the questionnaire more or less frequently than other workers. The questionnaire
addressed a variety of themes and did not emphasize problems with ageing, chronic
health conditions or work participation.
Selection bias
This study was explorative in nature because we used a descriptive design to increase our
knowledge of the workers’ experiences of problems due to ageing, obstacles they faced,
retention factors, their needs if they were to continue working and the differences
between workers with and without a chronic health condition. Furthermore, the self‐
reporting nature of the study could not be externally validated. Consequently, there may
be some bias in the classification of respondents on the basis of self‐reported data,
resulting in an underestimation of the differences and associations studied. However, it is
known from the literature that the self‐reporting of health status and of certain physical
chronic diseases (diabetes, cardiovascular disease, musculoskeletal and respiratory
problems) is reasonably reliable43. Therefore, we do not expect that the self‐reporting of
health and problems due to ageing introduced any significant bias, at least for these kinds
of health conditions. However, this expectation is based on a limited number of studies
concerning physical conditions and might not be generalizable to other physical or mental
health conditions.
Intervention study
Design
The intervention study meets most of the CONSORT criteria for high quality clustered
trials44,45. We used a quasi‐experimental design because a randomized controlled trial was
not an option when implementing the intervention in practice (chapter 7). Although the
General discussion
163
organizations participating were matched on the percentage of ageing workers and job
tasks, it is probable that the non‐randomized design might be biased.
A clustered design was used to minimize data contamination46. To correct for the
clustered design within the dependency of observations (supervisor, workers and
repeated measurements of one worker), multilevel analyses were used in the
effectiveness study (chapter 7).
The external validity of the intervention may be questionable as the intervention was
tailored to highly educated workers in a hospital and university. Performance of the
intervention called for a certain degree of independence and autonomy in the work
situation and job performance. The results may therefore not to be generalizable to lower
educated workers, for example, in manufacturing jobs.
Non‐response bias
The loss to follow‐up during the intervention was 30% after 12 months. This is in line with
a recently published study which found that loss to follow‐up is a common problem
among workplace intervention studies47. Participation levels in health promotion
interventions at the workplace are typically below 50%. The workers lost after the
baseline measure in our study were lower educated, suffered more fatigue, had lower
work ability scores and reported lower scores on the self‐efficacy scale ‘willingness to
exert effort in completing behaviour’ and ‘willingness to initiate behaviour’ and possibly
more vulnerable to remain active in the labour market. To overcome selection bias, these
baseline differences between completers and non‐completers in the intervention‐ and
control group were taken into account during the analyses.
Implementation in other age groups
From the preventive point of view, sustainable employability should start at the beginning
of a worker’s career. Although our intervention has been developed based on the
determinants and needs of workers aged 45 years and older, it can be hypothesised the
intervention can be useful for all age groups. The tailored approach of the intervention
offers workers a tool to enhance their problem‐solving capacity as a technique that is not
limited to specific problems or age related situations. Therefore, in our opinion, workers
of all ages can benefit from our intervention programme. Whereas it is preferable to
implement the intervention more broadly, it is recommendable to re‐evaluate the
effectiveness of the intervention in all age groups.
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164
Measurements
A third issue concerns the quality of some of the measurements. In our studies about
determinants and adaptation strategies of sustainable employability we used both the
total work ability index score and the single‐item work ability questionnaire. The total
work ability index is partly based on the presence of a chronic health condition. Having
one or more chronic health conditions automatically resulted in a decreased work ability
score, which does not take into account the type and severity of the health condition. This
may give too much weight to chronic health conditions, resulting in work ability scores
that underestimate the worker’s true capability.
In addition, we assumed that the impact of a chronic health condition on work ability also
depends on the position and occupation. For example, pain in the joints (e.g. knee or
lower back pain) might have more impact on workers with a high physical workload such
as blue collar workers, while memory recall problems or problems with sustained
attention would have more impact on office workers. It is in this context that we used the
single‐item work ability score to determine the impact of the presence of a chronic health
condition on work ability and the impact of psychosocial and work‐related factors on this
association. Previous studies have shown that the single‐item work ability questionnaire
could be used instead of the total Work ability Index48‐50.
The measures of work conditions in our study – to determine the impact of those
conditions on the association between the presence of a chronic health condition and
work ability – were sector, occupation, duration function and shift work (chapter 4). We
did not focus on work characteristics such as autonomy, or physical or mental demands, as
used in other studies. Previous research findings showed that work conditions, varying
from role ambiguity, physical climate, work schedule, repetitive movements or ergonomic
conditions, predict work ability6. Our limited focus may have caused an underestimate of
the impact of work conditions of sustainable employability and might explain that we
found a very small impact of work conditions on work ability.
General discussion
165
RECOMMENDATION FOR RESEARCH
The following recommendations for future research can be made:
To improve the content of the intervention ‘Staying Healthy at Work’ it is
recommended to include a monitoring system to assist workers to set up a
structured action plan after the dialogue including well‐defined and realistic
goals, and the organization of peer‐group support for supervisors.
To evaluate the effect of the revised version of the intervention ‘Staying Healthy
at Work’ it is recommended to use a randomized controlled design in a sample of
the total work population and a follow‐up period of more than one year. In
addition, a cost‐benefit analysis should be performed to allow employers to draw
balanced conclusions regarding the overall value of the intervention.
A more detailed process evaluation may assist the interpretation of the findings
of an intervention study. Future research of the process evaluation of the
intervention ‘Staying Healthy at Work’ should be undertaken on both worker and
supervisor level, which considers: a) reasons for not participating in the study, b)
whether the failure to develop an action plan is due to the fact that no problems
or needs were identified or whether they were solved directly through dialogue,
c) whether solutions were realized at the time of the evaluation. In addition,
determining why workers successfully perform the intervention or withdraw on
different stages of the intervention is recommended.
If the intervention is proven effective, it is important to investigate the usability
and effectiveness of the intervention in different occupational groups (e.g. blue
collar or white collar workers).
RECOMMENDATIONS FOR PRACTICE AND POLICY
This thesis demonstrated the importance of a tailored approach with individual
adjustments necessary to increase sustainable employability. We recommended
interventions that provide an individual strategy to enhance sustainable
employability and that might have benefit for workers of all ages.
Supervisors have an important role in the process of enhancing sustainable
employability. They can support workers to reflect on the changeability of
problems and needs experienced and the feasibility of solutions, not by taking
over the responsibilities but strengthen the own responsibility of workers to
create a healthy and motivated work situation. Therefore, employers should
invest in the supervisors ability how to challenge the workers and to perform a
dialogue with the workers about sustainable employability.
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Different conceptualizations of ageing are interrelated and have different effects
on work related outcomes. Future policy to enhance sustainable employability
should include different conceptualizations of ageing like chronological,
functional and organizational ageing with regard to sustainable employability.
Differentiation in intervention programmes to enhance sustainable employability
for workers with and without a chronic health condition is not necessary.
Nevertheless, workers with a chronic health condition might benefit most from
such interventions and policies because they experience more problems, thus
have more needs, and in general reported lower scores on predictors of
sustainable work ability (e.g. work ability, work attitude, physical functioning).
We recommend special attention for these workers.
We recommend a company‐wide integrated approach which guarantees close
collaboration between workers, supervisors, and human resource management,
and ensures that workers have the tools, resources, training and opportunities
for development needed to fulfil their responsibility to prolong working life
successfully. This approach fits very well with the broadly accepted definition of
sustainable employability developed in 2010: ‘sustainable employment implies
that workers throughout their working life have real opportunities/ a set of
capabilities – and the necessary conditions – that allows them to achieve valuable
work functioning in current and future work with preservation of health and
welfare. This implies a work situation (task and context) that facilitates them, as
well as the attitude and motivation to exploit these opportunities’ 51.
The benefits of investing in interventions to enhance sustainable employability
will take some time to become apparent. Employers should thus see investment
in sustainable work participation as part of a good employment strategy and their
social responsibility in the long term.
General discussion
167
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s
Summary
Summary
173
Ageing of the workforce exerts pressure on society with respect to health, wealth and
social insurance systems, which are inextricably linked. Older workers are more vulnerable
in the labour process, because of vitality and ageing problems affecting their daily
performance and their ability to meet job competence requirements. Given the fact that
the prevalence of chronic health conditions generally increases with age, and that workers
will be required to work longer, the prevalence of chronic health conditions in the work
place can be expected to increase even further in the coming decades.
To maintain the level of welfare, the challenge is to keep the ageing workforce healthy
and productive for about a decade longer than the mean retirement practice of the past
period. To enhance sustainable employability of ageing workers, knowledge about the
determinants of such sustainability as well as the views of workers concerning continuing
work until retirement age is required to understand how they might overcome workplace
challenges and for the development of interventions to enhance sustainable
employability. An occupational intervention that aims to increase sustainable
employability should assist workers to solve problems associated with their working life,
giving them confidence in their ability to effectively carry out actions which ensure their
sustainable employability.
The main objectives of this thesis are 1) to provide insight into needs and determinants
regarding a sustainable working life among workers aged 45 years and older with and
without chronic health condition, and 2) to develop and evaluate an intervention aimed at
enhancing sustainable employability (chapter 1). The first objective is addressed in
chapters 2 to 5, and the second objective in chapter 6 and 7. In
Chapter 8, the results of this thesis are summarized and discussed.
Chapter 2 describes an in‐depth survey study of the number and type of experienced
problems due to ageing, obstacles to perform work tasks, retention factors to maintain
work and support needs to continue working life in the next years for ageing workers with
and without a chronic health condition. The study was carried out in 3,008 workers aged
45 years and older, working in nine different companies.
Thirty‐seven per cent (n = 1,109) of the workers self‐reported the presence of a chronic
health condition. Problems due to ageing were experienced by 42 % of the workers, and
26% of those workers reported obstacles to perform work. Retention factors were
reported by 82% of the workers, and 38% reported that they had special support needs if
they were to continue working over the coming years. Workers with a chronic health
condition experienced more problems due to ageing (56 vs 34 %; p <.001), more obstacles
Summary
174
(42 vs 16 %; p<.001) and more needs (51 vs 31 %; p<.001) compared to those without a
chronic health condition. The type of problems, obstacles, retention factors and support
needs were very similar, with problems mostly related to physiological and psychological
functioning (e.g. loss of energy level or problems with long‐lasting attention), and
retention factors and needs mostly related to work‐related factors (e.g. relation with
colleagues or task reduction). These findings suggest that interventions aimed to enhance
sustainable employability of ageing workers can be similar for persons with and without
chronic health conditions and should have a central focus on work‐related factors.
Chapter 3 presents the results of a cross‐sectional survey study of workers aged 45 years
and older to determine the relationship between chronological age, functional age and
work outcomes (n=2,983). Chronological age referred to the calendar age. Functional age
referred to a worker’s performance and was measured with questions about perceived
health status and the presence of a chronic health condition. Work outcomes were
experienced problems due to ageing, obstacles, retention factors, support needs to
continue working life and work ability.
Based on chronological age, workers in the age groups 50‐54 and 55‐59 years of age
reported significantly more problems due to ageing and more support needs to continue
working life in the next coming years compared to workers between 45‐49 years of age.
Workers aged 50 years and older experienced less facilitators and reported a decreased
work ability compared to the workers between 45‐49 years of age.
The association of chronological and functional age of workers aged 45 years and older on
work outcomes were significant but small, except for the presence of a chronic health
condition which was not related to chronological age. Older workers (60–64 years)
reported better scores on social functioning, mental health and vitality compared with
workers aged 45–59 years.
With respect to functional age, predominantly a chronic health condition was associated
with more problems, more barriers, more support needs and lower work ability scores.
The results suggested that employers can increase sustainable employability by taking the
physical and cognitive ability necessary to carry out the work into account, and not just
the calendar age.
Chapter 4 describes a cross‐sectional study to determine the influence of work conditions,
psychosocial factors and perceived health on the association between the presence of a
chronic health condition and work ability among workers aged 45 years and older. The
aforementioned dataset was extended with workers of telecommunication company
Summary
175
(n=5,247). In addition, the variables associated with work ability for workers with and
without a chronic health condition were examined. This study showed that the presence
of a chronic health condition was negatively associated with work ability (B = ‐0.848). The
strength of this association slightly attenuated after subsequently adding individual
characteristics (B = ‐0.824), work conditions (B = ‐0.805) but more so after adding
psychosocial factors (B = ‐0.704) and especially perceived health variables (B = ‐0.049) to
the model. Variables associated with work ability for workers with and without a chronic
health condition were similar. Based on the lower mean scores for workers with a chronic
health condition on the work ability score as well for psychosocial factors and perceived
health, these workers might have the most benefit by a policy focussing on enhancing
those associated variables. Given these results, it may be a promising approach to address
perceived health as well as psychosocial factors in strategies and interventions towards a
sustainable healthy working life.
Chapter 5 examines the association of different coping styles with work ability among
workers aged 45 years and older, and if these association might depend on the extent of
job control and support (n=4,953). In addition, stratified analyses for differences in
associations between workers with and without a chronic health condition were
determined.
Active coping was positively associated with work ability (b=0.320; p<.001), whereas both
emotional and avoidance coping were negatively associated with work ability (b=‐0.243;
p<.001, b=‐0.363; p<.001 respectively). No interaction effect of job control and support
were found.
For workers with a chronic health condition, the association between active coping and
work ability was stronger, and job control had a small but positive effect on this
association. The negative association between the coping style expression of emotions
and work ability was stronger for workers without a chronic health condition. Emotional
support buffered the association between avoidance coping and work ability for workers
without a chronic health condition.
In today's society ‐with its dominance for self‐direction and its tendency to reframe
problems as challenges‐ the active coping style might be the most effective in the majority
of situations for workers aged 45 years and older. This seems especially true for workers
with a chronic health condition, and these workers can be further supported in their
adaptation by enhancing their job control.
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176
Chapter 6 describes the content of the intervention ‘Staying healthy at work’ and the
study design for evaluating the effectiveness of the intervention. The intervention aims to
enhance sustainable employability by increasing the workers’ problem‐solving capacity
and stimulating their awareness of their role and responsibility towards a healthy working
life.
The intervention comprised three stages: 1) the workers received a booklet focussed at
making an inventory of (work‐related) problems, needs, and career and personal
development opportunities. For these issues the worker was asked to assess the degree of
modifiability; 2) a dialogue between worker and supervisor to discuss solutions according
to a brainstorm format; and 3) making an action plan for the next year follow‐up period
for planning and implementing the solutions. The strategy of the intervention was to
change the workers awareness and behaviour by emphasizing their own decisive role in
attaining goals by giving them tools and support with which they can be effective in
carrying out the necessary actions. This may help them to learn that they can always
influence the impact of a situation by: (a) changing the situation by themselves; (b)
mobilizing the support of others; or (c) accepting the situation if it proofs to be
unchangeable. The intervention was incorporated into the annual appraisal procedure of
the organisations.
The supervisors in the intervention group were trained in taking the necessary actions by
means of stimulating self‐direction and enhancing knowledge and competencies. Workers
in the control group received business as usual; supervisors in the control group did not
participate in the training.
The primary outcome measures were vitality, work ability and productivity. The secondary
outcomes measures included fatigue, job strain, work attitude, self‐efficacy and work
engagement. Follow up measures were assessed after 3, and 12 months. A process
evaluation was conducted at both the supervisor and the worker levels, and satisfaction
with the content of the intervention was assessed.
Chapter 7 presents the effect evaluation of the problem‐solving based intervention
programme ‘Staying healthy at work’ compared to usual business within a quasi‐
experimental trial. Cluster randomisation on the level of the supervisor was used to avoid
contamination between workers.
The study included 236 workers from the University Medical Center Groningen (paediatric
and intensive care units) and the University of Groningen (technical services, secretarial
administrative services, financial economic affairs, human resource advice, facility services
and the library). The supervisors who agreed to participate were allocated in either the
Summary
177
intervention (n=12) or usual business group (n=7). Following the allocation of the
supervisors, the workers were divided to the intervention group (n = 129) or usual
business group (n = 107). After 12 months, data of 125 workers were available for the
analyses; 64 workers in the intervention group and 61 workers in the usual business group
respectively.
The problem‐solving intervention ‘Staying healthy at Work’ designed for workers to
enhance sustainable employability showed no superior effect on productivity and a
negative effect on work ability (B= ‐1.33, 95%CI ‐2.45 to ‐0.20) and vitality (OR=0.10,
95%CI 0.02‐0.46) compared to usual business. The secondary outcomes shows positive
effects for the scale perceived work attitude (B=5.29, 95%CI ‐9.59 to ‐0.99), the self‐
efficacy subscale persistence in the face of adversity (B = 1.45, 95%CI 0.42‐2.48) and the
subscale skill discretion of the psychosocial work characteristics (B = 1.78, 95%CI 0.74‐
2.83). No differences between the intervention and usual business group were found for
fatigue and work engagement.
In the process evaluation reported 43% of the workers (n=23) that the intervention had
increased their ability to clarify and explore problems with work participation and career
aspiration. About half of the workers reported to have become more capable in
conducting a dialogue with the supervisor about sustainable work participation (n=25;
46%) and to set up a structured action plan to improve work conditions after the
intervention (n=23; 44%). Fifty‐four per cent (n=29) of the workers stated that the
intervention had made them aware of the responsibility to create a healthy workplace,
and 37% reported that the intervention contributed to their self‐confidence in changing
the work situation for (n=20).
The conclusion of the intervention programme, whit its aim to encourage a self‐directed
cognitive behavioural process to enhance the workers’ problem solving capacity, is that
the intervention had no effect on productivity and a small but negative effect on work
ability and vitality. The positive results on the secondary outcomes and the results of the
process evaluation suggest that the intervention positively influenced the perspectives of
workers concerning their awareness and their feeling responsible for sustainable
employability.
Chapter 8, the general discussion, started with presenting the main findings in the light of
the study objective, followed by a discussion of methodological issues that should be
acknowledged when interpreting the findings.
Future research needs to develop a revised intervention including a monitoring system to
assist workers to set up a structured action plan after the dialogue including well‐defined
Summary
178
realistic goals, and the organization of peer‐group support for supervisors. Furthermore,
the effect of the intervention should be evaluated in a randomized controlled trial
representative for the total working population with a follow up of more than one year
and detailed process evaluation on both worker and supervisor level.
An important implication demonstrated in this thesis is that a tailored approach with
individual adjustments with attention to the different conceptualizations of ageing is
necessary to enhance sustainable employability, and that such a strategy might be useful
for workers of all ages. It is not necessary to differentiate for workers with and without a
chronic health condition in occupational intervention programmes regarding sustainable
employability and the benefits of interventions to enhance sustainable employable will
take time to become apparent. Moreover, an company‐wide integrated approach which
guarantees the close collaboration between workers, supervisors, and human resource
management, might ensure that workers have the tools, resources, training, and
opportunity for development needed to fulfil their responsibility to maintain and enhance
sustainable employable. Because individual agreements remains important to encourage
sustainable employability.
s
Samenvatting
Samenvatting
181
Door de hogere participatiegraad van oudere werknemers en de afname van de aanwas
van jongere werknemers door daling van het geboortecijfer (ontgroening) vergrijst de
beroepsbevolking. Om de productiviteit en daarmee het huidige welvaartniveau in onze
samenleving te behouden wordt van werknemers verwacht dat zij langer doorwerken.
Hierdoor worden werkgevers de komende jaren geconfronteerd met een
personeelsbestand waarin de oudere werknemer sterker is vertegenwoordigd dan
voorheen. De vergrijzing leidt eveneens tot aanzienlijke kostenstijging bij de
oudedagsregelingen en de gezondheidszorg, waarmee druk wordt gelegd op het sociale
zekerheidsstelsel. Door de toenemende participatie van oudere werknemers is de
aandacht voor de effecten van leeftijd en werk op zowel gezondheid als productiviteit
toegenomen. De maatschappelijke en wetenschappelijke uitdaging voor de komende
jaren is om de ouder wordende beroepsbevolking gezond, productief en duurzaam
inzetbaar te houden.
Gezondheid speelt een cruciale rol in het behouden van werknemers in het arbeidsproces.
Het aantal werknemers met chronische (gezondheids)klachten op de arbeidsmarkt zal
toenemen in de komende decennia, omdat de kans op het hebben van een chronische
aandoening toeneemt met de leeftijd. Diverse studies hebben aangetoond dat
gezondheidsproblemen een belangrijke reden vormen om het arbeidsproces vroegtijdig te
verlaten. Daarnaast heeft gezondheid ook een directe invloed op vitaliteit en op de
arbeidsproductiviteit. De impact van het ouder worden maakt het soms lastig om te
(blijven) voldoen aan de taken en eisen die worden gevraagd in het werk. Dit maakt de
ouder wordende werknemer kwetsbaarder in het arbeidsproces.
Kennis over hoe en wat werknemers nodig hebben om te kunnen blijven werken tot het
bereiken van de pensioengerechtigde leeftijd en de bepalende factoren die de duurzame
inzetbaarheid beïnvloeden is daarom gewenst. Deze kennis geeft inzicht in hoe oudere
werknemers omgaan met ervaren beperkingen op het werk en maakt het mogelijk om
interventies te ontwikkelen die bijdragen aan het vergroten van duurzame inzetbaarheid.
De doelstellingen van dit proefschrift, beschreven in hoofdstuk 1, zijn 1. inzicht te geven in
de ondersteuningsbehoeften voor werknemers van 45 jaar en ouder met en zonder een
chronische aandoening en factoren die van invloed zijn op hun duurzame inzetbaarheid en
2. het ontwikkelen en evalueren van een interventie om de duurzame inzetbaarheid van
werknemers te bevorderen. De resultaten met betrekking tot de eerste doelstelling
worden beschreven in de hoofdstukken 2 tot en met 5, de resultaten met betrekking tot
Samenvatting
182
de tweede doelstelling in de hoofdstukken 6 en 7. In hoofdstuk 8 volgen de conclusies en
worden de resultaten van de studies in dit proefschrift bediscussieerd.
In Hoofdstuk 2 wordt beschreven welke problemen werknemers ervaren in het werk door
het ouder worden en wat werknemers nodig hebben om het werk de komende jaren te
kunnen blijven uitvoeren. Hiervoor is een vragenlijstonderzoek uitgevoerd, waaraan meer
dan 3000 werknemers uit negen verschillende bedrijven hun medewerking verleenden. Er
is in de analyses onderscheid gemaakt tussen werknemers met en zonder een chronische
aandoening.
Zevenendertig procent (n=1109) heeft aangegeven een chronische aandoening te hebben.
Problemen door het ouder worden werd door 42% van de werknemers ervaren; 26% is
door deze problemen belemmerd bij het uitvoeren van het werk; 38% gaf aan
ondersteuning nodig te hebben om de komende jaren te kunnen blijven werken.
Werknemers met een chronische aandoening benoemden meer problemen door het
ouder worden (56% vs. 34%, p<.001), meer belemmerende factoren (42% vs. 16%, p<.001)
en hadden meer behoefte aan ondersteuning (51% vs. 31%, p<.001) in vergelijking met
werknemers zonder een chronische aandoening. De ervaren problemen bleken veelal
gerelateerd te zijn aan de fysieke en mentale gezondheid, zoals een verlaagd
energieniveau of problemen met langdurige concentratie. De ervaren ondersteunende
factoren en behoeften waren vooral gelegen in het werk, zoals de relatie met collega’s of
aanpassingen in het takenpakket. Er is geen aantoonbaar relevant verschil gevonden
tussen werknemers met en zonder een chronische aandoening.
De resultaten laten zien dat bij interventies ten behoeve van het bevorderen van
duurzame inzetbaarheid voor werknemers van 45 jaar en ouder geen onderscheid
gemaakt hoeft te worden tussen werknemers met en zonder chronische aandoening. Deze
interventies moeten zich vooral richten op werkgerelateerde factoren.
In hoofdstuk 3 wordt op basis van dezelfde vragenlijststudie de relatie tussen
chronologische leeftijd (kalenderleeftijd), functionele leeftijd (de eigen fysieke en
cognitieve vermogens om een functie goed te kunnen uitvoeren), ervaren problemen,
ondersteunende en belemmerende factoren, ondersteuningsbehoeften en werkvermogen
gepresenteerd. Functionele leeftijd is gemeten als ervaren gezondheid met subschalen
van de Rand36 en een vraag over de aanwezigheid van een chronische aandoening.
Werkvermogen is gemeten met de Work Ability Index.
Uit het onderzoek blijkt dat chronologische leeftijd samenhangt met ervaren gezondheid.
Werknemers in de leeftijdsgroepen van 50‐54 en 55‐59 jaar rapporteerden significant
Samenvatting
183
meer problemen door het ouder worden in vergelijking met werknemers in de
leeftijdsgroep van 45 tot 49 jaar. Werknemers van 50 jaar en ouder hebben een lagere
score op het werkvermogen en zij benoemden minder ervaren ondersteunende factoren.
Een samenhang tussen functionele leeftijd met ervaren problemen, ondersteunende en
belemmerende factoren, ondersteuningsbehoeften en het werkvermogen is aangetoond,
hoewel niet relevant. Significante samenhang werd alleen gevonden met de aanwezigheid
van een chronische aandoening (meer problemen, belemmerende factoren en
ondersteuningsbehoeften en een lager werkvermogen).
De resultaten laten zien dat werkgevers de duurzame inzetbaarheid van werknemers
kunnen vergroten door zich niet alleen te richten op chronologische leeftijd, maar vooral
de fysieke en cognitieve vermogens die nodig zijn om het werk uit te voeren in
beschouwing te nemen.
In Hoofdstuk 4 wordt beschreven in hoeverre er een samenhang bestaat tussen het
hebben van een chronische aandoening en het werkvermogen van werknemers van 45
jaar en ouder en welke persoons‐, werk‐, psychosociale‐ en gezondheidsgerelateerde
factoren deze samenhang beïnvloeden. De genoemde studiepopulatie is hierbij uitgebreid
met de werknemers van een groot telecommunicatiebedrijf, en betreft daarmee een
vragenlijstbestand van meer dan 5700 werknemers van 45 jaar en ouder.
De aanwezigheid van een chronische aandoening bleek negatief samen te hangen met het
werkvermogen (B=‐0,848). De toevoeging van de persoons‐, werk‐, en psychosociale
factoren aan het model beïnvloedden het verband (B=‐0,704), waarbij de toevoeging van
de variabelen over ervaren gezondheid de relatie tussen de aanwezigheid van een
chronische aandoening en het werkvermogen het sterkst bleek te beïnvloeden (B=‐0,049).
Een relevant verschil tussen variabelen die samenhangen met werkvermogen voor
werknemers met en zonder chronische aandoening is niet gevonden. Wel scoorden
werknemers met een chronische aandoening gemiddeld lager op het werkvermogen, de
psychosociale factoren en de ervaren gezondheid. Daarom is te verwachten dat een
interventie die zich richt op het verbeteren van deze factoren vooral voordeel oplevert
voor werknemers met een chronische aandoening.
De resultaten van deze studie laten zien dat het veelbelovend kan zijn om naast
gezondheid ook met name de psychosociale aspecten op te nemen bij interventies gericht
op het verbeteren van de duurzame inzetbaarheid van werknemers.
Hoofdstuk 5 presenteert de samenhang tussen verschillende manieren waarop
werknemers met problemen en stressoren omgaan (copingstijlen) en het werkvermogen.
Samenvatting
184
In de studie is gebruik gemaakt van vragenlijstonderzoek van de werknemers uit de tien
deelnemende organisaties waarvan de data over de uitkomstmaten in deze studie volledig
beschikbaar was (n=4953). Copingstijlen die worden onderscheiden in deze studie zijn
actief, emotioneel (ook wel passief) en vermijdend gedrag. Daarnaast is onderzocht of
deze samenhang wordt beïnvloed door een wisselwerking met de ervaren mate van
controle over het werk, en met emotionele en/of instrumentele steun.
Een actieve copingstijl bleek positief samen te hangen met het werkvermogen (B=0,320;
p<.001); emotioneel en vermijdend coping gedrag bleken negatief samen te hangen met
het werkvermogen (B=‐0,243; p<.001, B=‐0,363; p<.001). Deze samenhang is niet
afhankelijk van de mate van controle op het werk of de ervaren emotionele of
instrumentele steun. De samenhang tussen actieve coping en het werkvermogen bleek
sterker te zijn voor werknemers met een chronische aandoening; job control heeft een
kleine positieve invloed op deze samenhang. De negatieve samenhang tussen een
emotionele copingstijl en het werkvermogen bleek sterker aanwezig te zijn voor
werknemers zonder een chronische aandoening; voor deze groep geldt ook dat
emotionele steun een positief effect heeft op de negatieve samenhang tussen een
vermijdende copingstijl en werkvermogen.
De studie laat zien dat een actieve copingstijl in de huidige maatschappij – met een
verantwoordelijkheid van de werknemer om de eigen werksituatie actief te regisseren –
het meest effectief kan bijdragen aan het verbeteren van de duurzame inzetbaarheid van
werknemers van 45 jaar en ouder.
Hoofdstuk 6 beschrijft de ontwikkeling van de interventie 'Gezond aan het werk (blijven)'
en de opzet van het evaluatieonderzoek naar de effectiviteit van de interventie. Het is een
interventie met als doel het vergroten van het probleemoplossend vermogen van
werknemers. De interventiestrategie maakt werknemers bewust van de eigen rol en eigen
verantwoordelijkheid bij het creëren van een gezonde, motiverende en inspirerende
werksituatie. Leidinggevenden worden getraind om medewerkers te ondersteunen bij het
streven naar duurzame inzetbaarheid.
De interventie bestaat uit drie fasen: 1) een inventarisatie van ervaren (werk‐
gerelateerde) problemen, behoeften en persoonlijke ontwikkelingsmogelijkheden; 2) een
tweegesprek tussen werknemer en leidinggevende, waarin een brainstorm naar mogelijke
oplossingen plaatsvindt, en 3) het maken van een actieplan voor het komende jaar waarin
de werknemer specifieke oplossingen uitwerkt. Een stappenplan structureert het
doorlopen van de verschillende fasen van de interventie.
Samenvatting
185
De interventie biedt handvatten om werknemers te laten ervaren welke invloed zij zelf
kunnen hebben in het bereiken van doelstellingen of het ondernemen van acties om
inzetbaar te blijven. De interventie biedt ondersteuning bij het inschatten op welke wijze
verschillende situaties beïnvloedbaar zijn door: (a) het zelf veranderen van de situatie, (b)
ondersteuning van anderen te vragen, of (c) het aanvaarden dat een bepaalde situatie (op
dit moment) niet beïnvloedbaar is. De interventie kan worden opgenomen in de
bestaande gesprekscyclus tussen leidinggevende en medewerker zoals de
functioneringsgesprekken.
Vervolgens is een studie opgezet om de interventie uit te voeren in een testgroep en te
vergelijken met een controlegroep. Een dergelijke opzet maakt het mogelijk de
effectiviteit van de interventie te evalueren. De indeling in de interventie‐ of
controlegroep heeft plaatsgevonden op het niveau van de leidinggevende om te
voorkomen dat werknemers van één leidinggevende in zowel de controle‐ als de
interventiegroep terecht zouden komen. De primaire uitkomstmaten voor het meten van
de effectiviteit waren vitaliteit, het werkvermogen en de productiviteit. Daarnaast zijn als
secundaire uitkomstmaten vermoeidheid, de sociale en psychologische aspecten van werk
(taakeisen en regelmogelijkheden), de houding ten aanzien van werk, de eigen effectiviteit
en bevlogenheid gemeten. Vervolgmetingen vonden plaats na 3 en 12 maanden. Een
procesevaluatie is uitgevoerd op het niveau van de leidinggevende en de werknemer.
De resultaten van de effectstudie, uitgevoerd bij medewerkers van het Universitair
Medisch Centrum Groningen (kindergeneeskunde en diverse intensive care afdelingen) en
de Rijksuniversiteit Groningen (technische dienstverlening, secretariële/administratieve
diensten, financieel economische zaken, human resource advies, facilitaire diensten en de
bibliotheek), worden gepresenteerd in Hoofdstuk 7. De leidinggevenden die ingestemd
hadden met deelname werden op basis van instemming met deelname toegewezen aan
de interventie (n =12) of de controle groep (n=7). De leidinggevenden in de
interventiegroep ontvingen een training, de leidinggevenden in de controlegroep niet. De
deelnemende medewerkers werden, afhankelijk van hun leidinggevenden, toegewezen
aan de interventie (n = 129) of controlegroep (n = 107). De medewerkers in de
interventiegroep doorliepen alle fasen van de interventie; de werkwijze voor werknemers
in de controlegroep bleef ongewijzigd.
Van 125 werknemers waren na 12 maanden gegevens beschikbaar voor het meten van de
effectiviteit; 64 werknemers in de interventiegroep en 61 werknemers in de
controlegroep. Er is geen effect gevonden ten aanzien van productiviteit; wel was er een
Samenvatting
186
negatief effect op werkvermogen (B= ‐1,33; 95% BI ‐2,45 tot ‐0,20) en vitaliteit (OR=0.10;
95% BI 0,02‐0,46).
De secundaire uitkomstmaten lieten positieve effecten zien voor de ‘houding ten aanzien
van werk’ (B=5.29; 95% BI ‐9,59 tot ‐0,99), de subschaal ‘doorzetten bij tegenslagen’ van
de uitkomstmaat eigen effectiviteit (B=1.45; 95% BI 0,42‐2,48) en de subschaal ‘skill
discretion’ ‐in hoeverre medewerkers het gevoel hebben dat hun expertise wordt benut
binnen de organisatie en de mate waarin medewerkers het gevoel hebben nieuwe dingen
te leren binnen hun werk‐ van de sociale en psychologische aspecten van werk (B = 1.78;
95% BI 0,74‐2,83). Er is geen effect gevonden op vermoeidheid en bevlogenheid.
In de procesevaluatie rapporteerde 43% van de werknemers (n=23) door de interventie
beter in staat te zijn om ontwikkelingsbehoeften en knelpunten te benoemen. Ruim 40%
van de werknemers gaf aan na afloop van de interventie beter in staat te zijn een
tweegesprek over duurzame inzetbaarheid te voeren met de leidinggevende (n=25; 46%)
en een gestructureerd plan van aanpak op te zetten voor het verbeteren van de eigen
werksituatie (n=23; 44%). Vierenvijftig procent (n=29) van de werknemers gaf aan dat zij
door de interventie meer bewust waren van de eigen invloed op een gezonde en
motiverende werkomgeving en werksituatie; 37% vond dat het zelfvertrouwen om
veranderingen in de werksituatie tot stand te brengen was verbeterd (n=20).
De onverwachte negatieve resultaten kunnen worden veroorzaakt door keuzes die zijn
gemaakt tijdens de implementatie van de interventie in de praktijk en de wijze waarop de
diverse stappen van de interventie zijn uitgevoerd op het niveau van zowel medewerkers
als leidinggevenden. Ook de korte follow‐up periode en het feit dat onduidelijk is in
hoeverre duurzame inzetbaarheid al wordt besproken op de afdeling kunnen bijdragen
aan de negatieve resultaten op de hoofduitkomstmaten. Succesvolle elementen van de
oplossingsgerichte interventie betreffen het gegeven dat werknemers op korte termijn
anders tegen hun werk aankijken en dat werknemers zich meer bewust zijn van hun eigen
kunnen en eigen verantwoordelijkheid om inzetbaar te blijven. In hoeverre deze
interventie op de langere termijn ‐anders dan uit onze eerste resultaten blijkt‐ positief
bijdraagt aan de uitkomstmaten van duurzame inzetbaarheid dient nader onderzocht te
worden.
In hoofdstuk 8 zijn de belangrijkste resultaten van dit proefschrift samengevat en
bediscussieerd. De sterke kanten, methodologische overwegingen en beperkingen zijn
besproken. Tenslotte zijn aanbevelingen gedaan voor toekomstig onderzoek en voor
duurzame inzetbaarheid in beleid en de praktijk.
Samenvatting
187
Toekomstig onderzoek is nodig om een aantal stappen van de interventie nader uit te
werken, zoals bijvoorbeeld een monitoringsysteem om werknemers te ondersteunen bij
het opzetten van een gestructureerd actieplan met goed gedefinieerde en realistische
doelen na afloop van het tweegesprek. De organisatie van intervisiebijeenkomsten voor
leidinggevenden kan bijdragen aan de uitwisseling en het vergroten van de kennis over
hoe en op welke wijze leidinggevenden oplossingsgerichte ondersteuning kunnen bieden
aan werknemers. Tevens wordt aanbevolen om het effect van de interventie nogmaals te
evalueren in een gerandomiseerd onderzoek onder een representatieve groep
werknemers qua leeftijd en bedrijfssector. Hierbij is het wenselijk om de effectiviteit over
een periode van langer dan 12 maanden te meten en een gedetailleerde procesevaluatie
uit te voeren op het niveau van de werknemer en leidinggevende.
Het maken van onderscheid tussen werknemers met en zonder chronische aandoening is
niet nodig om te werken aan duurzame inzetbaarheid. Het is te verwachten dat een
organisatiebrede integrale aanpak, voor alle werknemers ongeacht leeftijd en in nauwe
samenwerking met werknemers, leidinggevenden en strategisch personeelsmanagement,
werknemers de middelen, (hulp)bronnen, opleiding en ontwikkelingskansen biedt die
nodig zijn om zelfstandig hun duurzame inzetbaarheid te verbeteren. Bij het streven naar
duurzame inzetbaarheid blijft maatwerk belangrijk.
R
Research Institute for Health Research SHARE
Research Institute for Health Research SHARE
191
This thesis is published within the Research Institute SHARE of the Graduate School of
Medical Sciences (embedded in the University Medical Center Groningen / University of
Groningen). Further information regarding the institute and its research can be obtained
from our internetsite: www.rug.nl/share.
More recent theses can be found in the list below.
((co‐) supervisors are between brackets)
2013
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Research Institute for Health Research SHARE
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Theunissen MHC. The early detection of psychosocial problems in children
aged 0 to 6 years by Dutch preventive child healthcare; professionals and
their tools (prof SA Reijneveld, dr AGC Vogels)
Bragaru M. Sports and amputation
(prof JHB Geertzen, prof PU Dijkstra, dr R Dekker)
Broesamle TC. Designing health care services using systems thinking; a
theory, a method and their application in the Dutch community pharmacy
(prof JJ de Gier, prof JJ van der Werf)
Jong J de. Antibiotics use in children; pharmacoepidemiological, practical and
environmental perpectives in the Netherlands (prof LTW de Jong‐van den
Berg, dr TW de Vries)
Rettke HG & Geschwindner HM. Long‐term outcomes in stroke rehabilitation
patients and informal caregivers (prof WJA van den Heuvel)
Research Institute for Health Research SHARE
193
Fortington LV. Enabling the elderly person with lower limb amputation
through surgery,rehabilitation and long term care (prof JHB Geertzen, prof
PU Dijkstra, dr GM Rommers)
Lako IM. Depressive symptoms in patients with schizophrenia; count
symptoms that count (prof K Taxis, prof D Wiersma)
Arnardottir AH. Regulatory benefit‐risk assessment; different perspectives
(prof FM Haaijer‐Ruskamp, prof PA de Graeff, dr PGM Mol, SMJM Straus)
Meijer A. The forest through the trees; investigating depression in patients
with cancer and patients with myocardial infarction using systematic reviews
and meta‐analytic techniques (prof P de Jonge, dr HJ Conradi, dr BD Thombs)
Kuchenbecker WKH. Obesity and female infertility
(prof JA Land, prof BHR Wolffenbuttel, dr A Hoek, dr H Groen)
Rozenbaum MH. Costs and effectiveness of extended vaccination strategies
against pertussis and pneumococcal disease (prof MJ Postma, prof E Hak)
Kingma EM. Intelligence and functional somatic symptoms and syndromes
(prof JGM Rosmalen, prof J Ormel, prof P de Jonge)
Kedde JH. Sexual health of people with disability and chronic illness
(prof HBM van de Wiel, prof WCM Weijmar Schultz)
Horst PGJ ter. Clinical pharmacology of antidepressants during pregnancy
(prof B Wilffert, prof LTW de Jong‐van den Berg)
Sinha R. Adjustment to amputation and artificial limg, and quality of life in
lower limb amputees (prof WJA van den Heuvel, prof P Arokiasamy, dr JP van
Dijk)
Research Institute for Health Research SHARE
194
2012
Pechlivanoglou P. Applying and extending mixed‐effects models in health in
health economics and outcomes research (prof MP Postma, prof JE Wieringa,
dr HH Le)
Verboom CE. Depression and role functioning; their relation during
adolescence and adulthood (prof J Ormel, prof WA Nolen, prof BWJH
Penninx, dr JJ Sijtsema)
Benka J. Living with rheumatoid arthritis: do personal and social resources
make a difference? (prof JW Groothoff, prof JJL van der Klink, dr JP van Dijk,
dr I Rajnicova‐Nagyova)
Kalina O. Sexual risky behaviour among Slovak adolescents and young adults;
social and psychological factors (prof SA Reijneveld, dr JP van Dijk, dr A
Madarasova‐Geckova)
Crijns HJMJ. Drug related safety issues affecting pregnancy outcome and
concerning risk minimisation measures; emphasis on pregnancy prevention
programmes (prof LTW de Jong‐van den Berg, dr SMJM Straus)
Vries HJ de. Working with pain; sustainable work participation of workers
with chronic non‐specific musculoskeletal pain (prof JHB Geertzen, prof JW
Groothoff, prof MF Reneman, dr S Brouwer)
Karsten J. On the threshold of disorder; definition and course of subthreshold
depression and subthreshold anxiety (prof WA Nolen, prof BWJH Penninx, dr
CA Hartman)
Abma FI. Work functioning: development and evaluation of a measurement
tool (prof JJL van der Klink, prof U Bültmann)
For more 2012 and earlier SHARE‐theses see our website.
D
Dankwoord
Dankwoord
197
Vanuit de praktijk st(r)oomde ik de wetenschappelijke wereld binnen vanwege mijn interesse
in onderzoek en startte ik het voorliggend promotieonderzoek. Ik verkeerde in de
veronderstelling dit onderzoek zelfstandig en ruimschoots binnen de 4 jaar af te kunnen
ronden. Inmiddels ben ik deze en andere illusies armer, maar gelukkig vele ervaringen rijker. Bij
een promotieonderzoek zijn meer mensen betrokken dan verwacht, waarbij ieder op eigen
wijze heeft bijgedragen tot de realisatie van dit proefschrift . Dat ik mijn promotietraject als
een zeer plezierige uitdaging heb ervaren vol mogelijkheden en kansen, komt juist door de
samenwerking met de vele betrokkenen. Mijn proefschrift zou dan ook niet compleet zijn
zonder dit dankwoord.
Een speciaal woord van dank gaat uit naar de verschillende bedrijven die hebben deelgenomen
aan de studies. Met name de mensen die zich sterk hebben gemaakt voor de introductie van
mijn onderzoek binnen hun organisatie en de deelnemende medewerkers wil ik van harte
bedanken. Jullie waren het die de toch behoorlijk uitgebreide vragenlijsten hebben ingevuld of
deel hebben genomen aan de interventiestudie. Bedankt, voor de openheid en het vertrouwen
waarmee velen mij als onderzoeker hebben ontvangen. Zonder jullie vrijwillige medewerking
was de uitvoering van mijn project niet mogelijk geweest. Bedankt voor jullie bijdrage aan de
nieuwe kennis en inzichten over duurzame inzetbaarheid!
In het bijzonder wil ik ook mijn promotoren Prof. dr. Jac van der Klink en Prof. dr. Johan
Groothoff en copromotor dr. Sandra Brouwer bedanken.
Beste Jac, dank voor het verrijken van ons projectteam als eerste promotor. Een lopend
onderzoek overnemen is niet eenvoudig, maar je expertise en ervaring binnen de
bedrijfsgezondheidszorg is een welkome aanvulling geweest in ons team en heeft veel
bijgedragen bij de ontwikkeling en implementatie van de interventie. De wijze waarop jij kennis
presenteert en overdraagt – rustig, correct en altijd met een positieve klank ‐ is zeer
inspirerend.
Beste Johan, met veel plezier denk ik terug aan onze uitjes naar de diverse bedrijven die we
benaderden voor medewerking aan ons project. De openhartige en olijke manier waarop jij
een gesprek de juiste kant op weet te draaien, maar met een duidelijke serieuze boodschap, is
prachtig. Daarnaast mijn verwondering over je snelle respons, de directe en positieve wijze
waarop je communiceert en de inspiratie die onze gesprekken opleverde. Met je inzetbaarheid
en enthousiasme ben je een voorbeeld voor mijn doelgroep.
Beste Sandra, dank voor het enthousiasme, je deskundigheid en de stimulans die ik door de
jaren heen heb mogen ontvangen. Je altijd daadkrachtige ondersteuning en scherpzinnigheid
zijn erg waardevol geweest bij het uitvoeren van dit project. Vaak hebben je opmerkingen mij
aan het denken gezet en leidde dit tot nieuwe inzichten. Daarnaast ben je gedurende mijn
onderzoektraject een voortreffelijke begeleider en ook een goede opleider tot onderzoeker
Dankwoord
198
gebleken, met oog voor nevenzaken die misschien nog wel belangrijker waren. Je deur stond
altijd open voor vragen of een goed gesprek en je zorg voor mijn gezondheid in de periode dat
mijn eigen inzetbaarheid het even liet afweten heb ik zeer gewaardeerd. Ik zie dan ook uit naar
onze samenwerking in de toekomst.
Dr. Boudien Krol wil ik graag bedanken voor haar rol als copromotor in de eerste jaren van het
project. Beste Boudien, de precisie waarmee jij als zeer gedreven onderzoeker werkt liet mij al
snel inzien wat wetenschap inhoudt. Je hebt mij getoond hoe belangrijk goede communicatie is
en ik waardeer het zeer op welke wijze je mij de vrijheid hebt gegeven om het onderliggende
project op te zetten. Je betrokkenheid bij zowel het project als bij mij als persoon was zeer
motiverend. Fantastisch dat er zo’n mooie nieuwe uitdaging op je pad kwam en wat fijn dat
onze wegen elkaar nog regelmatig kruisen. Dank voor de leerzame samenwerking.
Ik wil jullie graag allen danken voor het teamwork en het gestelde vertrouwen in mij
gedurende het project. Van iedereen heb ik jullie expertise, manier van aanpak en nog vele
andere zaken kunnen ‘afkijken’, die mij in de afgelopen jaren hebben gevormd tot
onderzoeker.
Ik dank de leden van de leescommissie prof. dr. ing. Lex Burdorf, prof. dr. Frank van Dijk en
prof. dr. Michiel Reneman voor het beoordelen van dit proefschrift.
De leden van de begeleidingscommissie, dr. Angela de Boer, drs. Jaap Bruins Slot, prof. dr. ing.
Lex Burdorf en dr. Bas Sorgdrager ben ik dankbaar voor de geschonken tijd en aandacht aan
mijn onderzoek. De bijeenkomsten waren zeer constructief en de balans tussen wetenschap en
praktijk werd grondig bediscussieerd en afgewogen. Na de bijeenkomsten zat ik altijd vol
plannen en nieuwe ideeën, alleen heeft het wel eens aan tijd ontbroken om deze allemaal tot
uitvoer te brengen. Jullie toegankelijkheid, binnen en buiten de bijeenkomsten, heb ik als zeer
bijzonder ervaren.
Suzanne Matthijssen en Hanneke Vervoort wil ik graag bedanken voor het uitzetten van de
vragenlijsten en verwerken van de data. Voor mij was het een leerzaam traject om jullie te
mogen begeleiden. Dank voor de prettige samenwerking.
Tijdens mijn project heb ik vele mensen leren kennen en gemerkt dat je als onderzoeker van
alle markten thuis moet zijn (is ook een belangrijke competentie…). Het was erg prettig om op
sommige punten ondersteuning te mogen ontvangen van de experts. Het gaat mij niet lukken
om iedereen hier persoonlijk te bedanken, maar ik wil graag laten weten dat ik ontzettend veel
heb mogen leren van de (veelal) HRM‐ers en medewerkers vanuit de bedrijfsgezondheidszorg,
die als aanspreekpunt fungeerden binnen de deelnemende bedrijven. Het was als onderzoeker
prettig om via jullie de ins en outs van de organisatie door te spreken, wat mij erg heeft
Dankwoord
199
geholpen om mijn onderzoek zodanig uit te voeren dat dit aansloot bij de praktijk. Deze
informatie helpt mij nog steeds om de praktijk niet uit het oog te verliezen bij het uitvoeren
van wetenschappelijke onderzoek.
Mijn collega’s op de 6e verdieping, waarvan sommigen ondertussen zijn uitgevlogen naar de 4e,
7e of elders, wil ik graag bedanken voor de plezierige contacten. We hebben heel wat te
bespreken gehad, al dan niet gerelateerd aan werk. Ook voor ‘tips and tricks’ stond er altijd wel
een deur open. Graag wil ik nog een aantal mensen in het bijzonder noemen. Michiel de Boer,
je kritische vragen en de verhelderende uitleg hebben mij zeer geholpen om te komen tot het
resultaat dat er nu ligt. Het is bewonderenswaardig hoe je de voor mij ingewikkelde
methodologische analyses kunt omzetten in praktische taal. Het is dan ook zeer plezierig om
ook in het vervolgproject methodologisch ondersteuning van je te mogen ontvangen. Roy
Stewart, dank voor de vragen die ik in de beginperiode bij je heb kunnen neerleggen met
betrekking tot powerberekeningen en mulitlevel analyses. Lida op ‘t Ende en Janneke Vos wil ik
graag danken voor hun ondersteuning bij het maken en inplannen van diverse afspraken. Het is
geen gemakkelijke klus om al die agenda’s te stroomlijnen, maar er werd altijd een plekje
gevonden of anders wel gecreëerd.
Iris Arends, Femke Abma en Haitze de Vries, erg leuk om met jullie te brainstormen over
toekomstmogelijkheden als postdocs. Ik hoop dat we er iets moois van kunnen maken! Ute
Bultmann, als overbuurvrouw stond je deur altijd open voor vragen. Ik zie uit naar onze
toekomstige samenwerking. Hardy van de Ven, onze samenwerking geeft mij nieuwe inzichten
en de feedbackmomenten zijn erg waardevol voor mij. Karin Veldman, ik hoop dat we in het
komende jaar weer gezellig gaan sporten want ik mis onze inspirerende gesprekken. Danielle
Jansen, dank voor de fijne gesprekken. Andrea Fokkens en Merlijne Jaspers, dank voor jullie
zorgzame opvang toen ik als kersverse promovendus op de afdeling neerstreek. Manna Alma,
Leenke Visser en Annemieke Luinge, bedankt voor jullie gezelligheid. En zeker ook niet te
vergeten de verschillende externe promovendi, die altijd bereid waren om vanuit hun eigen
invalshoek mee te denken naar oplossingen. Dank voor de interessante gesprekken.
Speciaal wil ik graag mijn kamergenoten Margriet Hielkema en Anja Holwerda bedanken voor
de vele gezellige momenten, de thee en niet te vergeten het plezier wat maakt dat een
werkplek motiverend is. Het bijeen plaatsen van drie zo totaal verschillende persoonlijkheden
is eigenlijk een klein sociologisch project. Kunnen we vanuit een psychologische invalshoek het
succes verklaren? Of is de demografische overeenkomst de verklarende variabele? Wat het
resultaat ook mag zijn, ik heb in ieder geval een hele goede tijd met jullie als kamergenoten
mogen beleven. Dank voor jullie zorg en steun die er altijd was. Ik hoop dat ik nog een tijdje
van jullie gezelligheid kan genieten.
Dankwoord
200
De collega’s van de RUG, het UMCG en de Hanzehogeschool Groningen die ik in de loop der
jaren heb leren kennen ‐ al dan niet door het werk ‐ en waar ik geregeld langs kon komen voor
het delen van visies, de impact van de (bestuurlijke en politieke) wijzigingen in de zorg of
gewoon een praatje wil ik graag bedanken voor hun betrokkenheid bij mijn werkzaamheden en
mij als persoon. Het is fijn om af en toe even vanuit een ander perspectief en een andere blik
naar bepaalde zaken te kijken. Dat heeft op mij altijd een zeer verfrissende werking gehad.
Het LUMC, met name Jan Maasen en Vivianne de Croon‐Koevoets, wil ik graag danken voor de
geboden mogelijkheid om de effectiviteit van de in dit proefschrift beschreven interventie te
kunnen onderzoeken in een vervolgstudie.
Vrienden en (schoon)familie, jullie geduld is gedurende dit traject (te) vaak op de proef gesteld
door het uitstellen van telefoontjes en afspraken. Manon Post, heerlijk dat ik altijd op je kan
rekenen als dat nodig. Karin Top‐Meijerink, je hebt mij laten zien hoe waardevol het leven is.
Het is erg verdrietig dat je niet meer onder ons bent. Onze fijne gesprekken, je optimisme en
je lach zette de ervaren werkdruk altijd in een ander perspectief. Sharon Haarmans en
Annemiek Rutte, door jullie ben ik uiteindelijk in het onderzoek gerold. Ik hoop dat we als VOD‐
jes snel weer eens bijeenkomen. Hoewel ik graag iedereen persoonlijk zou noemen die in de
afgelopen jaren om de één of andere reden voor mij belangrijk is geweest, zie ik in dat dit echt
niet gaat lukken. Weet dat ik jullie allen ontzettend dankbaar ben voor jullie steun en begrip. Ik
hoop dat ik nog lang van jullie onvoorwaardelijke vriendschap mag blijven genieten. Nu mijn
proefschrift is afgerond beloof ik beterschap!
Tot slot mijn trainingsmaatjes op de atletiekbaan, jullie wil ik graag bedanken voor de
betrokkenheid bij mijn werk, maar nog meer de afleiding en ontspanning die jullie mij
brachten. De plezierige omgeving heeft mij altijd rust en creativiteit gegeven.
Lieve pap en mam, jullie wil ik graag bedanken voor alle mogelijkheden en vrijheid die jullie mij
hebben gegeven om te doen en te laten wat ik wil. Dankzij jullie ben ik geworden wie ik ben en
kan ik zijn wie ik ben. Dank voor alle liefde en steun.
Cindy en Ruud, jullie zijn mijn allerliefste zus en allerliefste broer(tje). Het is voor mij speciaal
dat jullie mijn paranimfen willen zijn. Cindy, Pieter en Eric, bedankt voor alle overnachtingen
wanneer ik weer eens ver van huis moest zijn.
Lieve Kim, je komst, je vrolijkheid, je frisse en verwonderde blik op de wereld is veel meer
waard dan dit boek met letters. Er is niet mooiers dan met jou en je lieve papa samen te zijn.
Lieve Eddy, bedankt voor je liefde, vertrouwen, geduld en vooral onvoorwaardelijke steun.
Door de rust die je mij gaf, is jouw bijdrage aan dit proefschrift veel groter dan je denkt. Dankzij
jou is het gelukt; je bent erg bijzonder voor mij!
cv
Curriculum Vitae
Curriculum Vitae
203
Wendy Koolhaas is op 5 januari 1980 geboren in de Noordoostpolder. In 2007 begon zij
aan het promotietraject ‘duurzame inzetbaarheid van oudere werknemers’ op de afdeling
sociale geneeskunde, sectie arbeid en gezondheid, van het Universitair Medisch Centrum
Groningen. Binnen dit onderzoek beschreef zij welke problemen werknemers van 45 jaar
en ouder ervaren in het werk, wat zij nodig hebben om te blijven werken, welke factoren
invloed zijn op hun duurzame inzetbaarheid. Deze informatie is gebruikt om een
interventie te ontwikkelen gericht op het vergroten van de inzetbaarheid van
werknemers. De resultaten van dit onderzoek staan beschreven in dit proefschrift.
Naast haar promotietraject heeft Wendy meegewerkt aan diverse andere
onderzoeksprojecten op het gebied van duurzame inzetbaarheid, zoals het rapport
‘Duurzame inzetbaarheid van de oudere werknemer: stand van zaken’ en de ‘Handreiking
duurzame inzetbaarheid voor oudere werknemers, een integrale benadering voor
organisaties’. Tevens is zij betrokken bij het project ‘Shift Your Work’, met aandacht voor
de voorwaarden van duurzame inzetbaarheid van werknemers met onregelmatige
diensten, nacht‐ en ploegendiensten. Als vervolg op haar promotietraject heeft Wendy de
door haar ontwikkelde interventie ‘Oplossingsgericht werken aan Duurzame
Inzetbaarheid’ geïntroduceerd op een aantal afdelingen van het Leids Universitair Medisch
Centrum, ter bepaling van de effectiviteit.
Voor de start ging met haar promotieproject volgde zij de opleiding Medisch
Beeldvormende en Radiotherapeutische Technieken aan de Hanzehogeschool van
Groningen, afgerond met een adviesrapport voor het Sport Medisch Centrum Groningen
over “Botscan, de betekenis bij sportindicaties”. Omdat wetenschappelijk onderzoek haar
aansprak is zij daarna sociologie gaan studeren, waarbij de focus op arbeid lag. Deze
studie werd afgerond met een stage bij het Centrum voor Arbeid en Beleid (CAB) te
Groningen. Hier heeft zij onderzoek uitgevoerd naar implementatieverschillen tussen
gemeenten in Noord‐Nederland bij de invoering van de Wet Werk en Bijstand en de
invloed van externe factoren op de beleidskeuzes van gemeenten, resulterend in een
scriptie. Tijdens haar opleidingen is zij parttime werkzaam geweest als radiodiagnostisch
laborant in het Martini Ziekenhuis te Groningen. Hierna is zij gaan werken op de afdeling
Nucleaire Geneeskunde van het Universitair Medisch Centrum Groningen, waar zij haar
kennis vanuit beide opleidingen kon combineren. Naast de patiëntenzorg heeft zij
onderzoek verricht naar een minder belastende onderzoeksmethode voor patiënten om
osteoporose vast te stellen.
Curriculum Vitae
204
PHD PORTFOLIO SUMMARY
Research techniques Applied longitudinal data analysis Groningen, July 2012 Multi‐level analyses Maastricht, November 2008 Regression Analysis Rotterdam, August 2008 Medical Statistics Groningen, June 2008 Introduction Multi‐level analyses Groningen, January 2008 General research competences Science Writing January – September 2009 Project Management for Scientific Research Groningen, 2007‐2009 Publishing in English Groningen, September – December 2008
Presenting in English Groningen, June – September 2008 Reference Manager Groningen, February – March 2007 Depth and breadth of knowledge Intensieve taaltraining Engels Vught, May 2013 Career orientation for PhD students and scientific employees
Groningen, January – March 2013
Master class Public Health Research in Practice: how to develop effective interventions in public health practice
Wageningen, October 2012
Development and teacher training how to use the problem‐solving method in the dialogue about sustainable employability (for supervisors)
Groningen, 2009 Papendal, May 2010 Leiden, 2011‐2012
Supervising student , research employee, and PhD Groningen, 2010 ‐ present Tutoring medical students Groningen, 2007 ‐ 2009 Working with small groups Groningen, August 2007 Scientific international presentations International Conference on ‘Work, Well‐being and Wealth: Active ageing at Work’. Oral: Effectiveness of the ‘Staying Healthy at work intervention’. Poster: Chronic health conditions and work ability in the ageing workforce: the impact of work conditions, psychosocial factors and perceived health.
Helsinki, August 2013
EUPHA 5th annual European public health conference ‘All Inclusive
Public Health’. Oral: Effectiveness of a problem solving intervention for workers to promote sustainable employability. Oral presentations: abstracts. Eur J Public Health 2012; 22 (supplement 2), 28‐28.
Malta, November 2012
WDPI 2nd Scientific Conference on Work Disability Prevention and
Integration ‘Healthy ageing in a working society’. Poster: Chronic health conditions and work ability in the ageing work force: the impact of work conditions and psychosocial factors.
Groningen, October 2012
WDPI 1st Scientific Conference on Work Disability Prevention and
Integration. Oral: The impact of ageing problems, a chronic health condition, and type of occupation on a sustainable healthy working life.
Angers, September 2010
Curriculum Vitae
205
ICOH‐WOPS 4th International Conference on Psychosocial Factors of Work. Oral: Enhancing a sustainable healthy working life of older workers with a chronic disease. Poster: The workers' perspectives to enhance sustainable working life.
Amsterdam, June 2010
Expert meeting scientific network Work Ability Index. Oral: Towards a sustainable healthy working life. Results of a cross sectional study and development of an intervention.
Rotterdam, February, 2010
IV International Congress of Disability Management. Oral: Enhancing work participation of the older employee with a chronic disease.
Berlin, September 2008
National presentations VCD Humannet Oral: Hoe houden we mensen langer gezond aan het werk. Wat werkt voor de ‘oudere’ werknemer?
Oegstgeest, October 2013
Nascholing NVAB Kring Noord ’Healthy Ageing at Work’. Oral: Wat werkt voor de oudere werknemers? Hoe houden we mensen langer gezond aan het werk.
Groningen, April 2013
Nascholing NVAB‐Noord. Oral: Gezond aan het werk (blijven)! Resultaten en implementatie.
Haren, June 2010
Expertmeeting HRM professionals NFU/ SoFoKLES. Oral: Gezond aan het werk (blijven)! Resultaten en implementatie.
Utrecht, May 2010
Bedrijfsgeneeskundige dagen, VNAB Workshop: Oplossingsgericht werken aan duurzame inzetbaarheid.
Papendal, May 2010
Nederlands Congres Volksgezondheid ‘In balans’. Oral: Op weg naar duurzame inzetbaarheid van werknemers; factoren die arbeidsparticipatie beïnvloeden..
Rotterdam, April 2010
Bedrijfsgeneeskundige dagen ‘De kracht van de bedrijfsarts’. Poster: Wat hebben oudere medewerkers nodig om (duurzaam) inzetbaar te blijven?
Papendal, May 2009
Lerend netwerk Work ability Index Noord‐oost Nederland. Oral: Lossen we de oorzaken op of zoeken we oplossingen?
Deventer, March 2009
Nederlands Congres Volksgezondheid ‘Vroeg erbij, beter meedoen’ . Poster: Bevorderen arbeidsparticipatie van de oudere werknemer met een chronische aandoening.
Groningen, April 2008
PUBLICATIONS
Koolhaas W, De Boer MR, Groothoff JW, Brouwer S, Van der Klink JJ.
Coping, job control and social support as adaptation determinants of work ability among ageing
workers with and without a chronic health condition. Submitted, September 2013.
Koolhaas W, Groothoff JW, De Boer MR, Van der Klink JJ, Brouwer S. Effectiveness of a problem‐
solving based intervention to improve sustainable employability of ageing workers. Submitted,
December 2013.
Curriculum Vitae
206
Koolhaas W, Van der Klink JJ, De Boer MR, Groothoff JW, Brouwer S. Chronic health conditions and
work ability in the ageing workforce: the impact of work conditions and psychosocial factors. Int
Arch Occup Environ Health. 2013 May 16. [Epub ahead of print]
Koolhaas W, Van der Klink JJ, Vervoort JP, De Boer MR, Brouwer S, Groothoff JW. In‐depth study of
the workers' perspectives to enhance sustainable working life: comparison between workers with
and without a chronic health condition. J Occup Rehabil. 2013 Jun;23(2):170‐9. doi: 10.1007/s10926‐
013‐9449‐6.
De Vries H, Wessels M, Brouwer S, De Lange A, Koolhaas W, Van der Heijden B, Van der Mei S,
Bültmann U, Van der Klink J. Handreiking duurzame inzetbaarheid voor oudere werknemers, een
integrale benadering voor organisaties. Maart 2013, Universitair Medisch Centrum Groningen,
Rijksuniversiteit Groningen.
Brouwer S, De Lange A,Van der Mei S, Wessels M, Koolhaas W, Bültmann U, Van der Heijden B &
Van der Klink J. Duurzame inzetbaarheid van de oudere werknemer: stand van zaken. Overzicht van
determinanten, interventies en meetinstrumenten vanuit verschillende perspectieven. 2012, UMC
Groningen, Rijksuniversiteit Groningen. ISBN 978 94 6070 045 3
Koolhaas W, van der Klink JJ, Groothoff JW, Brouwer S. Toward a sustainable healthy working life:
associations between chronological age, functional age and work outcomes. Eur J Public Health.
2012 Jun;22(3):424‐9. Epub 2011 Mar 31 (Top publication award SHARE; top 25% artikel)
Koolhaas W, Brouwer S, Groothoff JW, van der Klink JJ. Enhancing a sustainable healthy working life:
design of a clustered randomized controlled trial. BMC Public Health, 2010; 10; 461
Jager PL, Jonkman S, Koolhaas W, Stiekema A, Wolffenbuttel BH, Slart RH. Combined vertebral
fracture assessment and bone mineral density measurement: a new standard in the diagnosis of
osteoporosis in academic populations. Osteoporos Int. 2011 Apr;22(4):1059‐68. Epub 2010 Jun 23.
Koolhaas W, Brouwer S, Groothoff JW, Sorgdrager B, van der Klink JJ. Bevorderen van de duurzame
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