Interaction between sleep duration and trouble sleeping on depressive symptoms among U.S. adults, NHANES 2015-2018

This study aims to examine the associations and interaction effects of sleep duration and trouble sleeping on depressive symptoms among U.S. adults. National Health and Nutrition Examination Survey (NHANES) data from 2015 to 2018 were analyzed (N = 10,044). Trouble sleeping and sleep duration were self-reported. Sleep duration was defined as short (≤6 h) or long (≥9 h), compared with normal (>6 and < 9 h). Depressive symptoms were determined by the Patient Health Questionnaire-9 score ≥ 10. Both multiplicative interaction and additive interaction were reported. There was a significant positive additive interaction between short sleep duration and trouble sleeping on depressive symptoms in the fully adjusted model (Relative excess risk due to interaction, RERIOR = 4.42, 95 % CI: 1.12, 7.73), with 43 % of the association with depressive symptoms attributed to the interaction (attributable proportion of interaction, AP = 0.43, 95 % CI: 0.22, 0.64). Similarly, a significant positive additive interaction between long sleep duration and trouble sleeping on depressive symptoms was found (RERIOR = 4.17, 95 % CI: 0.96, 7.38), with 41 % of the association with depressive symptoms attributed to the interaction (AP = 0.41, 95 % CI: 0.21, 0.60). No multiplicative interaction was detected between short or long sleep duration and trouble sleeping. The cross-sectional design limits the ability to draw causal inferences. Findings suggest that different aspects of sleep health interact synergistically, accounting for a substantial portion of the association with depressive symptoms. This underscores the importance of simultaneously considering multiple dimensions of sleep health in relation to depressive symptoms.