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Relationship Between Long Working Hours and Depression: A 3-Year Longitudinal Study of Clerical Workers

Amagasa, Takashi MD, MPH; Nakayama, Takeo MD, PhD

Journal of Occupational and Environmental Medicine: August 2013 - Volume 55 - Issue 8 - p 863–872
doi: 10.1097/JOM.0b013e31829b27fa
Original Articles

Objective: To clarify how long working hours affect the likelihood of current and future depression.

Methods: Using data from four repeated measurements collected from 218 clerical workers, four models associating work-related factors to the depressive mood scale were established. The final model was constructed after comparing and testing the goodness-of-fit index using structural equation modeling. Multiple logistic regression analysis was also performed.

Results: The final model showed the best fit (normed fit index = 0.908; goodness-of-fit index = 0.936; root-mean-square error of approximation = 0.018). Its standardized total effect indicated that long working hours affected depression at the time of evaluation and 1 to 3 years later. The odds ratio for depression risk was 14.7 in employees who were not long-hours overworked according to the initial survey but who were long-hours overworked according to the second survey.

Conclusions: Long working hours increase current and future risks of depression.

From the Department of Health Informatics (Drs Amagasa and Nakayama), Kyoto University School of Public Health, Sakyo-ku, Kyoto, Japan; and Department of Psychiatry (Dr Amagasa), Yoyogi Hospital, Sendagaya, Shibuya-ku, Tokyo, Japan.

Address correspondence to: Takashi Amagasa, MD, MPH, Department of Health Informatics, Kyoto University School of Public Health, Konoe-cho, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan (

Authors Amagasa and Nakayama have no relationships/conditions/circumstances that present potential conflict of interest.

The JOEM editorial board and planners have no financial interest related to this research.

Copyright © 2013 by the American College of Occupational and Environmental Medicine