What’s new?

C

OBESITY AND METABOLIC COMPLICATIONS

Childhood obesityLaura Stewart

Management programmes should use behavioural change tools

C A change in BMI SDS of �0.25 to �0.5 may reduce clinical risk

factors in obese children

C In severe obesity adolescents with co-morbidities, the use of

the anti-obesity drug, orlistat, could be considered under

supervision from specialists

C In extreme obesity, for adolescents with severe co-morbidities,

bariatric surgery could be considered

AbstractObesity is now a common childhood disease and is widely acknowledged

as having become a global epidemic. There are well-recognized health

consequences of childhood obesity, both during childhood and adult-

hood, affecting health and psychological welfare. Clinicians working

with obese children should have knowledge of the components of

a healthy lifestyle and understand the importance of interacting with

the child and family in a positive, empathetic and non-judgemental

manner. Most parents will be unaware of the impact of obesity in child-

hood and adolescence and many parents may even be unaware that

their own child is obese. UK Body Mass Index (BMI) centile charts with

the recommended cut-off points should be used to diagnose childhood

obesity. Evidence-based clinical guidelines conclude that treatment pro-

grammes should be multi-component, targeting changes in diet, physical

activity and sedentary behaviour (screen time). The use of behavioural

change strategies is consistently recommended in evidence-based guid-

ance on management. Guidelines suggest that in the case of severe to

extreme obesity in adolescents with co-morbidities, anti-obesity drugs

and bariatric surgery may be considered as part of a treatment plan.

Keywords adolescents; body mass index; body weight; childhood;

obesity; treatment

Childhood obesity is widely acknowledged as having become

a global epidemic.1,2 The prevalence of childhood obesity in the

UK dramatically increased over a short period of time in the early

1990s.3,4 The importance of childhood obesity has gained

national significance with the publication of expert reports5 and

evidence-based guidelines.6,7 Doctors in primary, secondary

and tertiary care are now more likely to see obese children and

adolescents in their everyday practice.

Definition

As in adult obesity, any definition of childhood overweight and

obesity needs to be able to define not only body fatness but also

the clinical relevance of this body fat. Body mass index (BMI) is

generally agreed to be the most appropriate proxy measure for

defining and diagnosing childhood obesity and overweight.6e8 In

childhood, because body fat and muscle mass alter with age and

differ between the sexes, BMI is meaningful only when it is

plotted correctly on age- and sex-specific BMI centile charts (UK

1990). All health professionals should use the UK 1990 BMI

centile charts for diagnosis and monitoring of treatment of

childhood obesity.6,7 The UK BMI centile charts are available

from Harlow Printing Ltd, South Shields, England.

Laura Stewart PhD RD RNutr is Team Lead, Paediatric Overweight Service

Tayside, NHS Tayside, and at the Children’s Weight Clinic, Edinburgh,

UK. Competing interests: none declared.

MEDICINE 39:1 42

Although there remains some disagreement on the precise

cut-off points to use for defining overweight and obesity on BMI

charts, both the SIGN 115 (2010) and NICE 43 (2006) guidelines

agreed on cut-off points in the UK of �91st centile as overweight

and �98th centile as obese,6,7 with SIGN 115 defining �99.6th

centile as severe obesity.7 These cut-off points have been shown

to be relevant to excess body fat and associated ill-health

consequences.6,7,9

Aetiology

An understanding of the complex aetiology of childhood obesity

is helpful to appreciate the changes required to manage obesity in

childhood. The causes of obesity are complex and multifactorial,

involving an interaction of our modern, obesogenic environment

and individual lifestyle choices. Because excess weight gain

occurs in a state of positive energy balance, increases in the

amount of calorie-dense foods eaten, and increases in screen

time (television, computer and video games) with a simulta-

neous decrease in the amount of physical activity undertaken by

children have been cited as reasons for the current epidemic.10,11

The understanding of the role of genetics in the predisposition

of some individuals to gain excess weight has improved in recent

years.12 However, for the vast majority of obese children, this

has not yet impacted on day-to-day clinical practice.13

Consequences

There is good evidence that childhood obesity persists (or tracks)

in to adulthood.14e17 The likelihood increasingmarkedly for obese

teenagers. A number of consequences of childhood obesity are

seen in childhood, adolescence and later in life. Clustering of

cardiovascular risk factors has been reported in children and

adolescents: high blood pressure, dyslipidaemia, abnormalities in

left ventricular mass and/or function, abnormalities in endothelial

function, andhyperinsulinaemia and/or insulin resistance. Abody

of evidence suggests that these cardiovascular risk factors are seen

in adults who were obese children or adolescents.13,14 There are

also instances of insulin resistance, type 2 diabetes and fatty liver

disease in obese adolescents.13,15,16 Psychological problems,

particularly in girls, have been reported in relation to low self-

esteem and behavioural problems. There are also long-term

consequences of social and economic effects, particularly in

women achieving a lower income.14,17 Table 1 gives a list of

consequences of obesity in children and adolescents that clinicians

should consider.

� 2010 Elsevier Ltd. All rights reserved.

OBESITY AND METABOLIC COMPLICATIONS

Assessment

If there are concerns that a child or adolescentmay be overweight or

obese, baseline measurements of weight and height should be

obtained and plotted on weight- and height-growth centile charts.

For children aged four years and under, the World Health Organi-

zation (WHO) growth charts should be used. BMI should be

calculated, and plotted at the correct age on the appropriate centile

chart for sex (UK 1990). The use of waist measurements in children

has gained support in recent years, and UK waist circumference

centile charts18 can be found on the flipside of the UK BMI centile

charts. However, there is no agreed cut-off point for defining level of

fat and thus those at health risk,9 and althoughwaistmeasurements

are a useful tool in monitoring progress in weight management,

they are not necessary for the current diagnosis of childhood

obesity.7,8

Particular consideration should be given to children and

adolescents who are obese but also of short stature, as this may be

an indication of a possible underlying endocrine cause of their

obesity, such as hypothyroidism, growth hormone deficiency,

Cushing’s syndrome or pseudohypoparathyroidism. Referral to

a paediatric endocrinologist should always be made for further

investigations.7,13 Young children, particularly those under 2 years

whohavehad a rapidweight gain, are severely obese and appear to

behyperphagicmayhave oneof the rare single genedefect causeof

their obesity and further investigations would be advisable.12 A

history of failure to thrive in infancy, and intellectual impairment

may alert the diagnosis of PradereWilli syndrome.

Discussing the subject of weight

There is a large body of evidence that shows many parents do not

recognize overweight and even severe obesity in their own

children.19e21 This can make the discussion of weight with

families daunting for clinicians and health professionals. Recent

work tells us that this should be approached directly, first with

the parents in an empathetic and non-judgemental

manner.20,22,23 Parents should be asked in a stepwise manner if

they consider their child’s weight a problem? Do they wish to do

any thing about their child’s weight? And what changes they feel

ready to make?22 Parents perceive a dialogue around their child’s

Consequences of childhood obesity2,13,14

C Cardiovascular disease

C Insulin resistance and type 2 diabetes

C Dyslipidaemia

C Hypertension

C Psychological and social morbidity

C Asthma

C Impaired fertility

C Orthopaedic e hips, ankles

C Breathing problems and sleep apnoea

C Fatty liver disease

C Some cancers

C Acceleration of puberty in both girls and boys

C Persistence of obesity into adulthood

Table 1

MEDICINE 39:1 43

physical activity levels as less threatening and less judgemental

of their parenting than questioning about their eating habits.23

Management

Management of childhood obesity is multifaceted, with inter-

ventions made complex by the interaction of the child or

adolescent with their parents and families. Parental weight is

known to influence the weight and lifestyle of the children in

a family, so the involvement of parents is fundamental to any

childhood weight-management programme.7,24 Recent guide-

lines and the Cochrane review25 on childhood obesity showed

a consensus on the following points:

� treatment should be commenced only when the parents are

ready and willing to make lifestyle changes

� treatment should be family based, with at least one of the

parents/carers involved.6,7,25

Table 2 summarizes the advice that should be given to children,

their parents and families. It is important to emphasis that changes

in total energy intake, screen time and physical activity are all of

equal importance in childhood weight management.7 Some

families are able to make positive changes when given simple

advice but the majority of children and parents will require to

attend an on-going group or individual programme over a number

of months. From current evidence, the optimal length of a weight-

management programme is unclear7 but programmes that include

the use of behavioural change tools would appear to be benefi-

cial.25 Clinicians should be aware of their local childhood weight-

management programmes and referral pathways.6,7

Outcomes

Weight maintenance in combination with increasing height

growth is an acceptable goal of treatment as this will lead to BMI

decreasing over time. For older adolescents, particularly those in

the very severe BMI range, weight loss may be required; if so,

a weight loss of 1e2 lbs per month would be advised.7 Most

research projects report outcomes as change in BMI standard

deviation scores (SDS). There is emerging evidence and debate

over the clinical significance of change in BMI SDS in children

and adolescents, particularly in relation to improvement in

insulin resistance, dyslipidaemia, and cardiovascular and

Recommended family lifestyle changes6,7,22

C Be physically active for 1 h per day (moderate to vigorous

intensity)

C Reduce screen time (sedentary behaviour, such as watching TV,

computers and playing computer games) to no more than 2 h per

day

C Encourage low-energy snacks (e.g. fruit, raw vegetables, a plain

biscuit)

C Avoid/cut down on high-energy foods such as crisps, chips,

chocolate, sweets

C Avoid grazing and keep food to meal times and small snacks

C Avoid sugary juice

C Parents should be positive about a healthy family lifestyle

Table 2

� 2010 Elsevier Ltd. All rights reserved.

OBESITY AND METABOLIC COMPLICATIONS

metabolic risk factors. At present, studies suggest a decrease in

BMI SDS ranging from �0.526 to �0.2527 may lead to an

improvement of risk factors in obese children.

Radical therapies

Practice points

C Weight issues should be discussed with the parent and child in

an empathetic and non-judgemental manner

C BMI centile charts should be used for the diagnosis of

childhood obesity

C Children with obesity who are of short stature should be

referred for further investigation

C Treatment programmes should target decreases in total

energy, reduction in screen time and increases in physical

activity levels

C Weight maintenance leading to a decrease in BMI is an

acceptable outcome.

Both the NICE 2006 and SIGN 2010 guidelines recommended that,

in certain circumstances and under close supervision, anti-obesity

drugs and bariatric surgery could be considered in adolescents.

Anti-obesity drug therapy could be considered for prescription to

obese adolescents who are attending a specialist weight-manage-

ment clinic.6,7 SIGN 115 further recommended that anti-obesity

drugs should be prescribed only for adolescents with severe

obesity (BMI >99.6th percentile) and with co-morbidities.7 Pres-

ently orlistat is the only anti-obesity drug available for use in the

UK, and is not licensed for use in children. It functions primarily by

preventing the absorption of fats, thereby decreasing the available

energy from the diet. It is recommended that patients are regularly

reviewed throughout the period of use, with carefulmonitoring for

side effects.7 Although in adults orlistat does not cause hypo-

vitaminosis, it does reduce circulating levels, so early vitamin

supplementation may be indicated for children.

Although bariatric surgery in children and adolescents is

uncommon in the UK, both guidelines suggest that bariatric

surgery for weight loss could be considered for post-pubertal

adolescents with very severe obesity and co-morbidities, and

stress that surgery should be undertaken only in a centre of

excellence in adult bariatric surgery.6,7 Since long-term side effects

of bariatric surgery in adolescents are unknown it is highly

desirable that follow-up should be for life. A

REFERENCES

1 World Health Organisation. Diet, nutrition and the prevention of

chronic diseases. WHO TRS 916. Geneva: WHO/FAO, 2003.

2 Lobstein T, Baur L, Uauy R, IASO International Obesity Task Force.

Obesity in children and young people: a crisis in public health. Obes

Rev May 2004; 5(suppl 1): 4e85.

3 Reilly JJ, Dorosty AR. Epidemic of obesity in UK children. Lancet 1999;

354: 1874e5.

4 Chinn S, RonaRJ. Prevalence and trends in overweight andobesity in three

crosssectional studiesofBritishchildren,1974e94.BMJ2001;322:24e6.

5 Foresight. Tackling obesity: future choices e project report 2007.

Government Office for Science.

6 National Institute for Health and Clinical Excellence. Obesity guidance on

theprevention, identification, assessmentandmanagementofoverweight

and obesity in adults and children. NICE Clinical Guidelines 43; 2006.

7 Scottish Intercollegiate Guideline Network (SIGN). Management of

obesity: a national clinical guideline. SIGN 115. Edinburgh 2010.

8 Reilly JJ. Assessment of obesity in children and adolescents:

synthesis of recent systematic reviews and clinical guidelines. J Hum

Nutr Diet 2010; 23: 205e11.

9 Reilly JJ, Kelly J, Wilson DC. Accuracy of simple clinical and epidemio-

logical definitions of childhood obesity: systematic review and evidence

appraisal. Obes Rev 2010; 11: 645e55.

10 Mulvihill C, Quigley R. The management of obesity and overweight: an

analysis of reviewsofdiet, physical activityandbehavioural approaches.

Evidence briefing. 1st edn. NHS Health Development Agency, 2003.

11 Prentice AM, Jebb SA. Obesity in Britain: gluttony or sloth? BMJ 1995;

311: 437e9.

MEDICINE 39:1 44

12 Farooqi IS, O’Rahilly S. Genetic factors in human obesity. Obes Rev

2007; 8(suppl 1): 37e40.

13 Han JC, Lawlor DA, Kimm SYS. Childhood obesity. Lancet 2010; 375:

1737e48.

14 Reilly JJ. Descriptive epidemiology and health consequences of child-

hood obesity. Best Pract Res Clin EndocrinolMetab 2005; 19: 327e41.

15 Drake AJ, Smith A, Betts PR, Crowne EC, Shield JP. Type 2 diabetes in

obese white children. Arch Dis Child 2002; 86: 207e8.

16 Sinha R, Fisch G, Teague B, et al. Prevalence of impaired glucose

tolerance among children and adolescents with marked obesity.

N Engl J Med 2002; 346: 802e10.

17 Reilly JJ, Methven E, McDowell ZC, et al. Health consequences of

obesity. Arch Dis Child 2003; 88: 748e52.

18 McCarthy HD, Jarrett KV, Crawley HF. The development of waist

circumference percentiles in British children aged 5e16.9 years. Eur J

Clin Nutr 2001; 55: 902e7.

19 Jain A, Sherman SN, Chamberlin LA, Carter Y, Powers SW,

Whitaker RC. Why don’t low-income mothers worry about their

preschoolers being overweight? Pediatrics 2001; 107: 1138e46.

20 Stewart L, Chapple J, Hughes AR, Poustie V, Reilly JJ. Parents’ journey

through treatment for their child’s obesity: qualitative study. Arch Dis

Child 2008; 93: 35e9.

21 Carnell S, Edwards C, Croker H, Boniface D,Wardle J. Parental perceptions

of overweight in 3e5 year olds. Int J Obes 2005; 29: 353e5.

22 Barlow SE, Expert Committee. Expert Committee recommendations

regarding the prevention, assessment and treatment of child and

adolescent overweight and obesity: summary report. Pediatrics

2007; 120: S164e92.

23 Reid M. Debrief of a study to identify and explore parental, young

people’s and health professionals’ attitudes, awareness and

knowledge of child healthy weight. 2008/2009 RE036. Edinburgh:

NHS Health Scotland, 2009.

24 Whitaker KL, Jarvis MJ, Beeken RJ, Boniface D, Wardle J. Comparing

maternal and paternal intergenerational transmission of obesity risk in

a large population-based sample. Am J Clin Nutr 2010; 91: 1560e7.

25 Luttikhuis HO, Baur L, Jansen H, et al. Interventions for treating

obesity in children. Cochrane Database Syst Rev; 2008.

26 Reinehr T, Andler W. Changes in the atherogenic risk factor profile

according to degree of weight loss. Arch Dis Child 2004; 89: 419e22.

27 Ford AL, Hunt LP, Cooper A, Shields JPH. What reduction in BMI SDS

is required in obese adolescents to improve body composition and

cardiometabolic health? Arch Dis Child 2010; 95: 256e61.

� 2010 Elsevier Ltd. All rights reserved.