抄録
Objective: To investigate the prospective association of leisure-time physical activity and commuting to work by walking with depressive symptoms among Japanese workers.
Methods: This study was based on one-year follow-up longitudinal survey data collected from 634 Japanese individuals（ 20-60 yr, 36.7±9.2 yr; 536 men） working at an information technology company and exhibiting no depressive symptoms at baseline. The duration of leisure-time physical activity and commuting by walking were measured using a self-report questionnaire. Additionally, depressive symptoms were defined as a CES-D（ Center for Epidemiologic Studies Depression Scale） score ≥ 16 points and/or usage of antidepressant drugs. All surveys were web-based and password-protected. Subjects were divided into tertiles based on the duration of leisure-time physical activity and on the duration of commuting by walking. Odds ratio（ OR） and 95% confidence interval （95% CI） of depressive symptoms were calculated using multiple logistic regression analysis adjusted for potential confounding factors such as age, sex, hours of sleep, alcohol consumption, smoking habit, baseline CES-D score, hours of overtime work, and job strain index（ Job Content Questionnaire）.
Results: Mean duration of leisure-time physical activity was 71.1±121.2 min/week and that of commuting by walking was 29.2±18.0 min/day. At one-year follow-up, 116（ 18.3%） workers experienced depressive symptoms. The adjusted OR of depressive symptoms in the highest tertile of leisure-time physical activity was 50% lower （OR=0.50, 95% CI=0.26-0.97） than that in the lowest tertile. In contrast, no significant association was found between the risk of depressive symptoms and duration of commuting by walking.
Conclusion: These findings suggest that leisure-time physical activity plays a role in the prevention of depressive symptoms among Japanese workers, independent of job stress, whereas commuting to work by walking has no antidepressive effect.
