A composite measure of sleep health is associated with symptoms of depression among Japanese female hospital nurses

Abstract

BackgroundIndividual dimensions of sleep health, including satisfaction, sleepiness/alertness, timing, efficiency, and duration, are associated with depression. We investigated whether a composite sleep health score is associated with symptoms of depression among Japanese female hospital nurses. MethodsParticipants were nurses (n = 2482, all women, age 31.2 ± 8.9 years) working at three general hospitals in Tokyo, Japan. A cross-sectional survey, conducted in 2015, assessed self-reported sleep and symptoms of depression. Sleep health was categorized as “good” or “poor” across five dimensions: satisfaction, daytime sleepiness, mid-sleep time, efficiency, and duration. A composite sleep health score was calculated by summing the number of “poor” dimensions. Depression was defined by depressed mood, loss of interest, or at least one of those symptoms (“depression symptoms”). Associations between sleep health and symptoms of depression were evaluated with multivariate logistic regression analyses, adjusting for sociodemographic factors and hypnotic medication use. ResultsIn multivariate logistic regression analyses, sleep health symptoms of poor satisfaction, efficiency, and duration were significantly associated with depressed mood; daytime sleepiness and poor efficiency were significantly associated with loss of interest; and poor satisfaction, daytime sleepiness, mid-sleep time, and efficiency were significantly associated with having at least one depressive symptom. The composite sleep health score was associated in a graded fashion with greater odds of depression symptoms. ConclusionIndividual and composite sleep health scores were associated with symptoms of depression. Assessing composite measures of multidimensional sleep health may help to better understand the well-known associations between poor sleep and depression and lead to improved intervention strategies.