Physical activity (PA) influences the risk of depression associated with long working hours

Background: Growing evidences showed that long working hours is associated with depression epidemic, but few studies investigate whether physical activity (PA) could modify the risk of depression associated with long working hours, which was the purpose of the present study. Methods: A cross-sectional data obtained from the National Health and Nutrition Examination Survey 2015-2018. According to the criteria of International Labour Organization, long working hours was defined as >40 h/wk. The Nine-item Patient Health Questionnaire (PHQ-9) was used to identify depression. Binary logistic regression and restricted cubic spline (RCS) models were used to estimate the associations between long working hours and depression, furthermore to estimate the association of PA. Results: 5958 participants were included in the study. The results indicated that 3074 (51.6 %) of participants worked >40 h/wk. The prevalence of depression was 7.7 %. Logistic regression analysis indicated a positive association between long working hours and depression [OR = 1.738, 95 CI (1.427, 2.117)], and the results were still robust after controlling other confounding factors. RCS models indicated that the high intensity PA group had the lowest risk of depression, followed by low intensity PA group and no PA group. Conclusion: Long working hours probably be associated with depression, while PA can modify the risk to some degree.