Long Working Hours and Risk of Depression by Household Income Level: Findings from the Korea National Health and Nutrition Examination Survey (KNHANES).

OBJECTIVES To investigate the relationship between working hours and the risk of depression according to household income level. METHODS We used the data from the Korea National Health and Nutrition Examination Survey. The information on working hours was obtained from the questionnaire, and depression was assessed by The Patient Health Questionnaire-9. After stratifying by household income level, the risk of depression for long working hour group (≥ 52 hours a week), compared to the 30-51 working hour group as a reference, were calculated using multiple logistic regression. RESULTS It was found that long working hours associated with high risk for depression in the group with the highest income, but not in the group with the lowest income. CONCLUSIONS The relationship between long working hours and the risk of depression varied by household income level.