Association between sedentary behavior and mental health among Japanese workers

Abstract

Objective: The purpose of this study was to investigate the association between sedentary behavior and mental health among Japanese workers. 　Methods: This study was a cross-sectional study. We collected survey data from annual health check-ups conducted in Meiji Yasuda Shinjuku Medical Center in Tokyo, Japan. The study participants comprised 9335 Japanese workers（5192 men and 4143 women; mean age 46.9 ± 10.8 years）without any psychiatric disease. A self-reported questionnaire gathered data on sedentary behavior, mental health（K6）, moderate to vigorous physical activity （MVPA, IPAQ）and potential confounding factors. Poor mental health was defined as a K6 score ≥ 13 points. Subjects were divided into four groups based on the total sitting time of the day. The odds ratio（OR）and 95% confidence interva（l 95% CI）of poor mental health were calculated using multiple logistic regression analysis adjusted for socioeconomic factors, lifestyle, MVPA and other potential confounding factors. 　Results: OR（95% CI）of poor mental health for men who had 12 or more hours per day of sitting time was 2.74 （1.24 － 6.04）. It was also confirmed that OR tended to increase the longer the sitting time（tend P < 0.01）. On the other hand, OR of poor mental health for women who had between 6 and 9 hours of sitting time per day was 0.52 （0.28 － 0.98）. However, there was no significant linear trend. 　Conclusion: In Japanese male workers, long sitting time is associated with poor mental health, even after adjustments for socio-economic factors, lifestyle, occupational factors, and MVPA. Compared to the group with under 6 hours of sitting time per day, the group with over 12 hours per day suffered more than twice as much poor mental health. On the other hand, no significant linear trend in the relationship between sitting time and poor mental health was found among women.