V i brat ion disorders of mai l

I nternatimal symposium on the protection of workers aga i nst v i bra- tion, ILO 1982 295-306

motorcycl i sts

Fuhuchi J . , Hosoka- wa,M. & Nishiyama, K.

International Symposium on the Protection of Workers Against

Med jwnarodni simgozi jum o zagtiti vadnika od vibraci ja

Proceedings of the International Symposium on the Protection of Workers Against Vibration, NiS, 21 -24 Septembre 1982.

Zbornik radova sa Medunarodnog simpozijuma o zaititi radnika od vibracija, NiS, 21 -24 sep tembar, 1982. godine

VIBRATION DISORDERS OF MAIL MOTORCYCLISTS Y. Fukuchi De'paFtment of Preventive Medicine, Shiga University of Medical Science, Japan

M. Hosoka wa Kyoto City lnstitute of Public Health, Japan

K. Nishiyarna ,

lnstitute of Hygiene and Applied Physiology, ETH Zurich, Switzerland

Introduction

Since the late 1960s vibration disorders among motorcyclists

have been reported in some Japanese occupations, i.e. laundry-

men (l), forestry-watchmen ( 2 ) , test-motorcyclists ( 3 1 , de-

livery women of lactic acid beverage ( 4 ) , bill collectors ( 3 )

and rnailmen (3) .

It was noticed that patients suffering from vibration disorders

caused by the chainsaw, increased their symptoms when riding

on motorcycles ( 5 ) .

The Ministry of Post and Telecommunications introduced motor

scooters at the beginning of the 1950s for special delivery

service and motorcycles around 1955. The number of motorcycles

for this occupation reached 84.131 in 1979. The motorcycles

have gradually been used for various purposes and finally for

the normal mail delivery. The type of motorcycles has developed

into large engine displacement.

The number of accidents caused by motorcycles remarkably in-

creased from 1.859 in 1966 (68% of the registered accidents

under official driving duties) to 4.830 in 1975 (80%) as

shown in Figure 1.

The motorcycles used by the Minsitry were specially manufactured

for them and more importance was attached to horsepower and

carrying capacity than to the driver's comfort.

The results of measurement of the vibration levels of motor-

cycles used by the Ministry showed that the vibration level

of t h e handles and t h e s e a t s exceeded t h e 4 t o 8 hours l e v e l

proposed by IS0 f o r a l l speeds and sometimes even t h e 1 t o 2

hours l e v e l o r t h e l e v e l f o r l e s s than 30 min f o r r i d i n g on

rough and 'bad roads , on roads covered wi th snow o r f o r d r i v ing

wi th high speed (6, 7 1 .

4 Motorcycles ' a cc iden t -- I N o of motorcycles

Total l abour a cc iden t

/ /

.....-... Cars acc iden t , ..- --------=.No a of bicycle S a

C H

6 0 6 l ~ b 1 6 1 b i ~ b : r j r 0 ; ~ 3 i 2 ~ ~ 4 ~ Year

Figure 1: Number of used mail motorcycles and t h e i r

a cc iden t s .

Index number: 100 i n 1966

The i n v e s t i g a t i o n of t h e phys io log ica l l oad when r i d i n g t h e

motorcycle showed t h e fol lowing r e s u l t s (-8, 9 ) :

- The s k i n s u r f a c e temperature decreased and t h e v i b r a t i o n . .

s ensa t i on t h r e shq ld l e v e l increased. . ..

- t h e recovery t ime increased wi th t h e r i d i n g du ra t i on

- The f a c t o r s of co ldness , season and wind v e l o c i t y in f luenced

t h e responses i n t h e nega t ive .

Ques t ionna i re Study

I n o rde r t o f i n d o u t t h e r e a l s t a t e of work1 oad a nd h e a l t h of

t h e workers on o u t s i d e du ty of t h e Min i s t r y of Pos t and Tele-

currmrunications, t h e survey was c a r r i e d o u t by ques t i onna i r e s

throughout t h e country i n January and February 1979 a s shown

i n F igure 2 . Spec i a l importance was a t t a ched t o t h e v i b r a t i o n .

disease. The s u b j e c t s were a l l members of t h e Trade Union of t h e

Ministry of Pos t and Telecomrnunicati~ns (sampled branches)

296

on outside duty. Their number was 16.529 and the number of

responses was 14.895 (rate of response: 90.1%).

Maflrnen on outside duty

118,000

Motorcycles: 84,000 ( 0 .

Mail motorc~clists I ) 80,000

S a m ~ l e d districts

,;l' Responses

14.895 90.1 -X

Figure 2: First questionnaire survey for mail motor-

cyclists, January and February 1979.

The following points were assessed by questionnaire:

- Professional career and riding career on motorcycles

- present condition - - -... . . - subjective symptoms when riding on the motorcycle

- medical history

- daily subjective symptoms

- treatment of disease

- measures to be taken by the Ministry and the Workers Union

Results

Working conditions ,

Table 1 shows that 70.2 % of the respondents were engaged in - .

the delivery and 94.8 3 were engaged to ride motorcycles (in

the following they are called motorcyclists). . . - . , .- /

Table 1: Workinq condi t ions o f ' mailmen n = 14 .a95

Job

Transport

Years of ex-

per ience with

motorcycles

Col lec t ion and d e l i v e r y

Saving .

Insurance

Saving and Insurance

A l l above

Other S

Motorcycle

Motorcycle and b i cyc l e

Motorcycle, car & b i c y c l e

Car

Bicycle .

Walking ----p

2 20 years

15 - 19

10 - 14

5 - 9

Ratio %

Table 2: Workinq condition's of mo to rcyc l i s t s n = 13.857

Working condi t ions

Riding days/week

6 days 5 4

S 3

r a t e %

Table 2 (continued}

Working conditions

Hour s/day

s6 hours 5 - 6 4 - 5 3 - 4 < 3

Covered distance/day r 5 0 km 4 0 - 49 30 - 3 9 2 0 - 29

20

Riding speed

650 km/h 40 - 49 30 - 39 20 - 29 < 2 0

Pavinq condition o f the roads

mostly unpaved many unpaved hal f and hal f many paved most ly /a l l paved

-- -

Frequency of s lopes

mostly more hal f and hal f l e s s f ew/no

rate %

No of le t ters /day * 2 1000 letters

8 0 0 - 999 600 - 7 9 9 400 - 599

*) This percentage i s for the xnailmen on c o l l e c t i o n and

de l ivery d u t y (n = 5798)

Daily subjective symptoms - . . . .

. . L - - . - A. . . . . . . Table 3: Daily subjective symptoms of the mailmen on out-

side duty

***: p 0.001, **: p < 0.01. *: p 0.05, n.s.:,no

significance x2-test between Motorcyclists and others.

White finger

j hand/ finger

Numbness 1 upper extremities at night I lower extremities

hand/ f inger upper extremities

at night .

Pain i elbows hand joint knees foot joint low back .

Stiffness in hand n morning

Motor- cyclist

n = 13.857

- * .. . Severe stiffness c i pain in neck,-"-

shoulder and arm 64.0 1

Chill 1 body 38.5 hand or finger 1 31.7

Gastric disorders . 1 4 4 . 9

Others

n = 733

-p

Signi- f icancc

n . s . ***

*** *** ***

* *** *** ** n.s. *** ***

*** *** *** ***

The number of motorcyclists who complained about an increase of

suffering from "white fingers", "numbness of hand/fingersW or "pain in hand/fingersM is 2.1 to 7.4 larger than the number of

persons showing a decrease in complaints.

96.4 % of persons with "white'finge'r" -suffer-more from it in

*inter. Colder regions of the country show higher prevalences

for "numbness of hand/fingerN . - .:-. -

Subjective symptons during or after riding on the motorcycle

Table 4: Subjective symptons during or after riding on the

motorcycle '(n = 13.857) '

( Always 15.9 % Sense of intense vibration sometimes/ at cer- 1 tain places 72.6 %

I I upper extremities 6 7 . 0 %

Senbitive site of intense lumber , hip 5 9 . 4 % Vibration 1- abdominal organs 34.5 %

Numbness of arm, hand or finger 36.3 8

Pain in arm, hand or finger 24.8 %

White finger 3.1 %

Difficulty to keep the spinalcolumn straight because of low back pain 2 4 . 0 %

Stiffness of shoulder or neck 55.2 %

Worgening of bleeding of hemorrhoid 2 9 . 5 %

Difficulties to write clearly because of hand tremor 22.4 %

1

Most of the subjective symptoms shown in Table 4 increased

apparently with the riding distances, with 'the inclinations

and had quality of the roads (Fig. 3). The prevalences also

show relevant relations with days and hours on the motorcycle.

The number of persons complaining about "white fingern,

"numbness of hand/fingern or "pain in hand/fingerN increase

with the riding distances, the ratio of inclination of the

road and the bad quality of the road. (Figure 4 ) .

O r s t a n c c Covcrci l by Ridinq

S oav Proport on of Sloping Road Propact i o n o f llrlprvcd ~ o a d

5 6 F S-F s ~ F

S G F S > €

S : SLOPE

F : FLAT

P only P > U P< U

PS'U P=U PC<U

I J : IJNPAVED

P : PAVED

Figure 3: Preva lence r a t e s of symptoms on and/or a f t e r r i d i n g a motorcycle s e t up accord ing

t o s e v e r a l - c u r r e n t c o n d i t i o n s of work.

note: Numbers i n pa r en the se s i n d i c a t e t h e fo l lowing symptoms:

(1) Fee l ing s t i f f i n shou lde r or neck ( 2 ) Becoming numb i n arm, hand o r f i n g e r by v i b r a t i o n ( 3 ) Fee l ing p a i n i n t h e back ( 4 ) Fee l i ng p a i n i n arm, hand or f i n g e r (5) Becoming d i f f i c u l t t o t a k e f i rm g r i p ( 6 ) Worsening or b l eed ing of hemorrhoid ( 7 ) Becoming d i f f i c u l t t o keep s t r a i g h t t h e s p i n a l column wi th low back pa in ( 8 ) Becoming d i f f i c u l t t o w r i t e c l e a r l y because of tremor of hands ( 9 ) Having headacke o r f e e l i n g unwell (10) Fee l i ng p a i n i n t h e elbow (11)Fee l ing v e r t i g o o r becoming unsteady (12) Ge t t i ng f r o s t b i t t e n (13) Cyanot ic changing i n f i n g e r ( 1 4 ) White f i n g e r (15) whi te toe

Ratio of sloping road

Covered distance in a day

Ratio of unpaved road

Figure 4: Incidence of whitening, numbness or pain in

hand/finger and some working conditions for

each experience years' group of the motorcycle

(on delivery duty)

ExperSence years 0 less than S years

5 5 - 9 years A 10 - 14 years

15 years or more

Health examination .-

The results of the heatlh examinations done by us with other

collaborators for about 1000 motorcyclists of the Ministry,

show khat patients suffer mainly from peripheral circulatory

disorders, back/lumber pains as well as from neck-shoulder-

arm paSns. About 30 % of the employees needed medical treat-

ment. powever, the number of the serious vibration disorders

is smaller than in forestry. Moreover there are many patients

who soon recover after an early medical treatment or after

having.exchanged the motorcycle for a bicycle.

Measures

The Mipistry of Post and Telecomunications has been slow to

take mFasures such as registration, health examination and

preventive t reatment of v ibra t ion d isorders of motorcyclis ts .

Things only s t a r t e d moving when t h e Trade Union and t h e Re-

search Group s t a r t e d the inves t iga t ions . Recently the Ministry

began t o introduce ca r s ; t h e v ib ra t ion l e v e l of motorcycles i s

being decreased, heatable handles a r e f i t t e d . They a l s o paid

a t t e n t i o n t o speed l i m i t s and t o road condit ions and organized

hea l th examinations e t c . However, we w i l l have t o wait u n t i l

t h e ev ident r e s u l t s of these measures a r e known.

Table 5: Preventive measures aga ins t motorcycl i s t s ' d i sease

proposed by Zentei Shokugyobyo Kenkyukai (Research

Committe together with Commission of t h e National

Post and Telecommunication' S Worker union) i n 1980

I . Limits f o r the use of motorcycles

Max. allowed hours: 2h/day, 8h/week and 32h/month

Max. allowed consecutive minutes: 30 min

Max. allowed consecutive days: 2 days

Max. allowed speed: 40 km/h

Max. allowed covered distance: 150 km/week

Use of c a r s i n t h e bad road area

Use of c a r s i n bad weather period o r in tense cold,

Establishment of a new system i n b ig c i t i e s r not

re ly ing on motorcycles alone.

Use of c a r s f o r spec i a l de l ivery .

11. Improvement and inspect ion f o r t h e s a f e t y of motorcycles

1. More than 10 dB decrease of v ib ra t ion l e v e l compared t o t h e present motorcycle

2 . Anti-wind/cold equipments, such a s windscreens, hea table handlesr boot bumpers f a r safe ty .

3 . Improvement of t h e r id ing comfort and easy use.

4 . Improvement of t h e present inspec t ion f o r safe ty .

i Measurement of v ibra t ion and publ ica t ion of t he r e s u l t s . .

Table 5 (continued] l

111. Improvement of occupational safety and health manage-

ment

1. Periodical patrol of the road conditions and of their improvement by the employer and employees.

2. Periodical education of motorcyclists in occupational safety and health.

3. ~stablishment/improvement of the rest room/depository on the intermediate road for the collection and delivery rounds.

4. Provision of clothes, gloves, portable heater etc.for protection against the cold.

5. Restroom with equipment for heating, warm bathing, gargling, washing eyes and possibilities to obtain warm drinks and meals

6. Revision of laws for the traffic safety of mailmen on out- side duty. Limitation of mailmen's rounds in relation to the bad road condition.

IV. Medical check-up and care system for motorcyclists' disease

Medical examination for an early detection and treatment.

Training/instruction of medical staff and preparation of medical institutions/equipments.

Quick organisation system of job change or reduction of the mdtorcycle duty for mailmen showing symptoms at the special medical examination.

Early registration of the disease under official duties as vibrqtion disorder etc, apparently caused by the use of motorcycles. Arrangement for necessary medical treatment, sick leave and compensation of wages etc. Freedom of the workers to choose a medical doctor.

Relevant instruction of staff to undertake preventive medical treatment and; (health consultation/guidance.

Prohibition of riding on motorcycles for workers suffering from diseases which risk to worsen by the use of motorcycles.

Es;tablishment of a safe, good and correct system of mail

coJlection and delivery

The present plan of using mainly motorcycles should be modi- fikd; walking, bicycles and cars should also be taken into consideration.

Table S (cont inued)

2. A second examination should be c a r r i e d o u t and t he number of personnel on motorcycles ' du ty should be increased. Working hours should be shortened and t h e i n t roduc t i oh of a five-day week acce le ra ted .

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