Vol.3, No.9, 537-541 (2011)
doi:10.4236/health.2011.39090
C
opyright © 2011 SciRes. Openly accessible at http://www.scirp.org/journal/HEALTH/
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: miyarin@med.kagawa-u.ac.jp
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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538
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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539539
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
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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 (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
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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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