Affiliations: Department of Hygiene and Public Health, Nippon
Medical School, Tokyo, Japan
Note: [] Address for correspondence: Tomoyuki Kawada, Department of
Hygiene and Public Health, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-Ku,
Tokyo 113-8602, Japan. Tel.: +81 3 3822 2131; Fax: +81 3 5685 3065; E-mail:
kawada@nms.ac.jp
Abstract: Background: Lifestyle determinants of depressive state and a feeling
of unhappiness in daily life were evaluated among the workers in Japan by
adjusting obesity and age. Methods: A total of 3630 men aged 34 to
60 years from a workplace in Japan participated in this cross-sectional study
conducted in 2006. The prevalence of depressive state and a feeling of
unhappiness were evaluated by a questionnaire with questions pertaining to the
age, body mass index, and six lifestyle factors. The six lifestyle factors were
frequency of exercise and alcohol intake per week, smoking habit, hours of
sleep per day, and frequency of eating breakfast and snack per week. The
associations between depressive state and/or a feeling of unhappiness and the
lifestyle factors were tested by logistic regression analysis. Results: The prevalence of depressive state and a feeling of unhappiness among the
workers was 8.1% and 20.3%, respectively. The prevalence of workers who
sleep at least for 6~hours on average, exercise regularly and eat breakfast
everyday increased as the age of the workers increased. Depressive state and a
feeling of unhappiness were significantly associated with age and a reduced
duration of sleep even after adjustment for the other variables. No significant
associations were found between the other lifestyle factors examined and
depressive state and/or a feeling of unhappiness. Conclusions: Depressive
state and/or a feeling of unhappiness were significantly associated with a
reduced duration of sleep among the workers. Aging was a preventative factor of
depressive state and/or a feeling of unhappiness. The effect of obesity was
adjusted in this study, but the cause-effect relation between lifestyles and
depressive state and/or a feeling of unhappiness should be clarified by the
follow-up study.
