Long and short sleep duration are both associated with suicidal ideation in Korean employees

The aim of this study was to investigate the association between self-reported sleep duration and suicidal ideation in Korean employees. We studied 204,629 employees who attended health screenings in 2014. Total sleep duration was assessed with a self-reported question and categorized in one of 7 subcategories: ≤4, 5, 6, 7, 8, 9, and ≥10 h per day. Suicidal ideation was assessed with a self-reported question. Depression and anxiety symptoms were assessed with the Korean version of the Center for Epidemiologic Studies Depression scale and the Beck Anxiety Inventory, respectively. Occupational stress was assessed with the Korean Occupational Stress Scale, Short Form, a self-report questionnaire. We used multiple logistic regressions to calculate odds ratio of suicidal ideation according to self-reported sleep duration category, after adjusting for sex, age, occupational stress and either depression or anxiety. The prevalence rate of suicidal ideation was higher at both extremes of sleep duration and lowest at 7 h per day, showing a U-shaped curve. The odds ratio for suicidal ideation increased in groups of less than or equal to 6 h and greater than or equal to 10 h of sleep. Long and short sleep duration are both associated with suicidal ideation in Korean employees. The results of this study suggest that self-reported sleep duration might be used as a behavioral indicator for screening possible suicidal ideation in employees.