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

Background: This study aims to examine the associations and interaction effects of sleep duration and trouble sleeping on depressive symptoms among U.S. adults. Methods: 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. Results: 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. Limitations: The cross-sectional design limits the ability to draw causal inferences. Conclusions: 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.