Relationship between work style and cigarette smoking in Japanese workers

doi:10.4236/health.2011.39090

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Vol.3, No.9, 537-541 (2011)

doi:10.4236/health.2011.39090

Health

Relationship between work style and cigarette smoking

in Japanese workers

Nobuyuki Miyatake1*, Kenji Nishii2, Takeyuki Numata3

1Department of Hygiene, Faculty of Medicine, Kagawa University, Kagawa, Japan;

*Corresponding Aut hor: [email protected]

2Okayama Health Foundation Hospital, Okayama Health Foundation, Okayama, Japan;

3Okayama Southern Institute of Health, Okayama Health Foundation, Okayama, Japan.

Received 30 June 2011; revised 1 August 2011; accepted 9 August 2011.

ABSTRACT

We investigated the link between work st yle (i.e.

day work and shift work) and cigarette smoking

in Jap ane se worker s. W e used d at a of 3,238 men

(39.3 ± 10.5 years) and 5,111 women (37.1 ± 10.9

years), aged 20 - 59 years, by cross-sectional

clinical investigation study. Work style i.e. day

work and shift work, cigarette smoking, status

of stress and stress coping were obtained by

questionnaires by well-trained medical staff. A

total of 227 men (7.0%) and 339 women (6.6%)

were shift workers, and 1346 men (41.6%) and

649 women (12.7%) were current smokers. W ork

style was significantly linked to cigarette smok-

ing, stress and stress coping after adjusting for

age in women. In addition, the level of stress

coping in subjects with cigarette smoking was

significantly low er than that in subjects w ithout

cigarette smoking ev en af ter adjustin g for age in

women. However, these associations were not

noted in men. Work style was critically associ-

ated w ith cigarette smoking in Japanese female

workers.

Keywords: Work Style; Shift Work; Cigarette

Smoking; Stress Coping

1. INTRODUCTION

Economic globalization needs continuous processing

or operations around the clock to optimize manufactur-

ing system. A 24-hour continuous operation system has

become more popular and shift workers have become

also more popular in Jap an. Several reports h ave show ed

that shift work is associated with coronary artery disease

[1], hyper cholesterolemia [2,3], weight gain [4] and

hypertensio n [ 5] .

Cigarette smoking is an important public health chal-

lenge, and it has been reported that 39.4% of men and

11.0% of women are current smokers in Japan [6].

Cigarette smoking is also a strong risk factor for athero-

sclerosis and cardiovascular disease in a dose-dependent

manner [7]. However, the link between work style such

as day work and shift work, and cigarette smoking in

Japanese workers still remains to be investigated.

Therefore, in this study, we evaluated the link be-

tween work style and cigarette smoking and the effect of

stress and stress coping on cigarette smoking in Japanese

workers.

2. SUBJECTS AND METHODS

2.1. Subjects

We used data for 3238 Japanese male workers (39.3 ±

10.5 years) and 5111 women (37.1 ± 10.9 years), retro-

spectively from a database of 16,380 subjects who met

the following criteria: 1) they had wanted to change their

lifestyle i.e. diet and exercise habits, and had received an

annual health check-up from June 1997 to Dec 2009 at

Okayama Southern Institu te of Health, 2) received evalua-

tion of work style, cigarette smoking, status of stress and

stress coping as part of the annual health check-up, 3)

they were day workers and/or shift workers, aged 20 - 59

years, and 4) provided written informed consent (Table

1).

Ethical approval for the study was obtained from the

Ethical Committee of Okayama Health Foundation.

2.2. Work Style

Subjects completed a self-administered questionnaire.

This included the following question regarding patterns

of work style: During your work ing life, un til the pr esen t,

what shift (time of day) did you work most: mainly day

time, mainly night (i.e. fixed-night shift), or alternate

N. Miyatake et al. / Health 3 (2011) 537-541

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Table 1. Clinical profiles of enrolled subjects.

Men Women

Number of subjects 3238 5111

Age 39.3 ± 10.5 37.1 ± 10.9

Height (cm) 167.0 ± 5.8 157.2 ± 5.4

Body weight (kg) 71.2 ± 11.7 54.8 ± 9.2

Body mass index (kg/m2) 24.6 ± 3.7 22.2 ± 3.6

Abdominal circumference ( cm) 83.9 ± 10.2 70.3 ± 9.2

Hip circ umference (cm) 94.6 ± 6.2 91.0 ± 6.1

Mean ± SD

night and daytime (that is, rotating-shift work)? In this

study, we excluded 65 male and 131 female night work-

ers to evaluate the influence of shift work on cigarette

smoking compare to day workers.

2.3. Exposure Data

The self-administered questionnaire also inquired

about other characteristics of smoking status (never or

current smoker), status of stress (yes or no) and stress

coping (yes or no ).

2.4. Anthropometric Measurement s

The anthropometric parameters were evaluated by us-

ing the following respective parameters such as height,

body weight, body mass index (BMI), abdominal cir-

cumference, hip circumference. BMI was calculated by

weight/[height]2 (kg/m2). The abdominal circumference

was measured at the umbilical level and the hip was

measured at the widest circumference over the tro-

chanter in standing subjects after normal expiration [8].

2.5. Statistical Analysis

Data are expressed as mean ± standard deviation (SD)

values. A comparison of parameters was performed by

χ2 test and logistic regression analysis: p < 0.05 was con-

sidered to be statistically significant. Statistical analysis

was performed with StatView 5.0 (SAS Institute Inc.,

Cary, NC, USA).

3. RESULTS

A total of 227 men (7.0%) and 339 women (6.6%)

were shift workers, and the rate of shift workers was the

highest in 20’s in both sexes (Table 2).

Table 3 shows the comparison of cigarette smoking

as classified by age group. Current smokers were de-

creased with age in both sexes, and 1346 men (41.6%)

and 649 wom en (1 2.7%) were current sm okers.

We also evaluated the status of stress (Table 4). 2071

men (64.0%) and 3,735 women (73.1%) women an-

swered as having stress, and the rate of subjects with

having stress was the highest in 30’s in both sexes.

However, subjects with having stress coping was com-

parably lower [1539 men (47.5%) and 2730 women

(53.5%)] (Table 5). The rate of subjects with having

stress coping was the highest in 20’s in men and in 50’s

in women.

In addition, we evaluated the relationship between

work style and cigarette smoking, status of stress and

stress coping. In women, the rate of current smoker and

having stress was significantly higher in shift workers

than those in day workers after adjusting for age (Table

6). The rate of having stress coping in shift workers was

significantly higher than that in day workers after ad-

justing for age. In men, those clear associations were not

noted.

Finally, we investigated the relationship between

cigarette smoking and status of stress and stress coping

(Table 7). The rate of having stress coping in current

smokers was significantly lower than that in non smok-

ers even after adjusting for age in women, but not in men.

The relationship between cigarette smoking and status of

stress was not noted in both sexes.

4. DISCUSSION

We evaluated the link between work style and ciga-

rette smoking in Japanese workers and we found that

close associations between shift work and cigarette

smoking in female workers. In addition, having stress

coping might be important for Japanese female workers

for prohibiting smoking.

In some literatures, work style was closely associated

with cigarette smoking especially male workers. Fujino

et al. reported that the rate of current smoker was higher

in shift male workers (59.5%) than that in day male

workers (55.4%) in Japan Collaborative Cohort Study

for the Evaluation of Cancer Risk (JACC Study) [1].

Dochi et al. also reported that the rate of current smoker

was higher in shift workers (68.8%) than that in day

workers (58.8%) in male workers in steel company [2].

Suwazono et al. also showed that shift work was closely

associated with cigarette smoking in male workers [4].

There were few studies that evaluated the relationship

between shift work and cigarette smoking in Japanese

female workers. Kageyama et al. reported that the

prevalenve of current smoker was 29%, being higher

than that in the general population of Japanese women

by evaluating 522 Japanese female staff nurses [9]. In

this study, it is note worthy that we found the relation-

ship between work style and cigarette smoking in wo men

N. Miyatake et al. / Health 3 (2011) 537-541

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even after adjusting for age. However, those associations

were not noted as previous study in men. Enrolled sub-

jects in this study were undertaken health check-up and

they wanted to change their lifestyle. Therefore close

associations might not be noted in men.

According to the relation between work style and status

of stress, 3-shift system of employment increases work-

related stress [10]. Parkes carried out cross-sectional

Table 2. Comparison of work style as classified by age group.

Men Women

Day work % Shift work % Day work % Shift work %

20 - 29 661 90.4 70 9.6 1575 90.0175 10.0

30 - 29 888 92.6 71 7.5 1135 93.579 6.5

40 - 49 790 93.7 53 6.3 1207 95.359 4.7

50 - 59 672 95.3 33 4.7 855 97.026 3.0

Total 3011 93.0 227 7.0 4772 93.4339 6.6

Table 3. Comparison of cigarette smoking as classified by age group.

Men Women

Cigarette smoking (+) % Cigarette smoking (–) % Cigarette smoking (+)% Cigarette smoking (–)%

20 - 29 329 45.0 402 55.0281 16.11469 83.9

30 - 29 413 43.1 546 56.9179 14.71035 85.3

40 - 49 349 41.4 494 58.6130 10.31136 89.7

50 - 59 255 36.2 450 63.859 6.7 822 93.3

Total 1346 41.6 1892 58.4649 12.74462 87.3

Table 4. Comparison of stress as classified by age group.

Men Women

Stress (+) % Stress (–) % Stress (+) % Stress (–) %

20 - 29 443 60.6 288 39.41297 74.1453 25.9

30 - 29 645 67.3 314 32.7925 76.2289 23.8

40 - 49 566 67.1 277 32.9910 71.9356 28.1

50 - 59 417 59.1 288 40.9603 68.4278 31.6

Total 2071 64.0 1167 36.03735 73.11376 26.9

Table 5. Comparison of stress coping as classified by age group.

Men Women

Stress coping (+) % Stress coping (–) % Stress coping (+) % Stress coping (–) %

20 - 29 377 51.6 354 48.4957 54.7793 45.3

30 - 29 419 43.7 540 56.3642 52.9572 47.1

40 - 49 405 48.0 438 52.0631 49.8635 50.2

50 - 59 338 47.9 367 52.1500 56.8381 43.1

Total 1539 47.5 1699 52.52730 53.42381 46.6

N. Miyatake et al. / Health 3 (2011) 537-541

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Table 6. Relationship between work style and cigarette smoking, stress and stress coping.

Men Cigarette smoking (+) Cigarette smoking (–) p p (After adjusting for age)

Day work 1248 1763

Shift work 98 129 0.6113 0.7664

Stress (+) Stress (–)

Day work 1924 1087

Shift work 147 80 0.7950 0.8360

Stress coping (+) Stress coping (–)

Day work 1419 1592

Shift work 120 107 0.0951 0.1054

Women Cigarette smoking (+) Cigarette smoking (–)

Day work 574 4198

Shift work 75 264 <0.0001 <0.0001

Stress (+) Stress (–)

Day work 3444 1328

Shift work 291 48 <0.0001 <0.0001

Stress coping (+) Stress coping (–)

Day work 2505 2267

Shift work 225 114 <0.0001 <0.0001

Table 7. Relationship between cigarette smoking and stress, stress coping.

Men Stress (+) Stress (–)

ｐ

p (After adjusting for age)

Cigarette smoking (+) 840 506

Cigarette smoking (–) 1231 661 0.1208 0.1053

Stress coping (+) Stress coping (–)

Cigarette smoking (+) 602 744

Cigarette smoking (–) 937 955 0.0070 0.1054

Women Stress (+) Stress (–)

Cigarette smoking (+) 496 153

Cigarette smoking (–) 3239 1223 0.0396 0.0797

Stress coping (+) Stress coping (–)

Cigarette smoking (+) 321 328

Cigarette smoking (–) 2409 2053 0.0307 <0.0001

research targeting 736 two-shift workers and 1131 day

workers at an oil refinery, and concluded that the 2-shift

workers had higher job demand and less job control over

their work [11]. In female workers, Kageyama et al. re-

ported that the cigarette smoking-dependent tendency

was associated with recent life events and the presence

of insomnia [9]. Stress is probably the most important

contributor to excess smoking levels [12]. American

study showed that officers who smoked experienced

high-stress levels more than twice that of non smokers

[13]. Therefore, stress coping may important for prohib-

iting cigarette smoking. Serxner et al. recommended that

N. Miyatake et al. / Health 3 (2011) 537-541

541541

smoking cessation and prevention programs should fo-

cus on change in individual coping mechanisms [14].

We also found that the rate of stress in shift smokers was

higher than that in day workers and the rate of stress

coping was also higher in shift workers than that in day

workers after adjusting in women. Although the rate of

stress coping was higher in shift workers than that in day

workers, the rate of stress coping was significantly lo wer

than in current smokers than that in non smokers in

women. Taken together, it seems reasonable to suggest

that simply recommending proper stress coping except

cigarette smoking, might result in decreased cigarette

smoking in some Japanese female workers.

Potential limitations remain in this study. First, our

study was a cross sectional and not a longitudinal study.

Second, the 3238 Japanese male workers and 5111

women, all of whom wanted to change their lifestyle,

underwent measurements for this study: they were there-

fore more health-conscious than the average person. In

fact, in men, clear associations were not noted the rela-

tionship between shift work and cigarette smoking as

previous studies [1,2,4]. Third, we could not obtain the

data of the average number of cigarettes smoked per day

or subject’ age when they started smoking. Subjects who

smoked before the date of the analysis but who had

stopped by then would have therefore been categorized

as non-smokers. Fourth, status of stress and stress coping

was evaluated by simple questionnaire (yes or no).

Therefore, further prospective studies are needed in Jap-

anese workers to prove the link between work style and

cigarette smoking.

5. CONFLICT OF INTEREST

There is no conflict of interest.

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