Depression as a potential mediating pathway in the associations between healthy lifestyle and sleep status: a cross-sectional analysis of NHANES 2013–2020

Abstract Background Existing studies have primarily focused on the independent effects of healthy lifestyle or depression on sleep status, yet there is a lack of systematic research examining the potential mediating pathway of depression between healthy lifestyle and sleep status. This study aims to explore how depression may mediate the relationship between healthy lifestyle and sleep status among U.S. adults. Methods This study included 5,532 participants from the NHANES 2013–2020. Healthy lifestyle was assessed using a composite health lifestyle score (range: 0–6) based on diet quality, smoking status, alcohol consumption, body mass index, physical activity, and sedentary behavior. Depression was assessed using the Patient Health Questionnaire-9 (PHQ-9; range: 0–27), with higher scores indicating more severe symptoms. Sleep status was evaluated using two indicators: sleep duration (reflecting sleep quantity) and trouble sleeping (reflecting subjective sleep quality). Weighted multivariable linear and logistic regression models were used to examine the associations between healthy lifestyle, depression, and sleep status. Additionally, a mediation model was constructed to explore the potential mediating pathway of depression. Subgroup and sensitivity analyses were performed to assess the robustness of the results. Results With each one-point increase in the healthy lifestyle score, sleep duration significantly increased by 0.066 h [β: 0.066, (95% CI: 0.027, 0.105), P = 0.002], and the odds of trouble sleeping were 0.786 [(95% CI: 0.730, 0.847), P < 0.001]. Compared with the poor healthy lifestyle (0–2 points), the optimal lifestyle (5–6 points) slept 0.258 h longer [β: 0.258, (95% CI: 0.121, 0.394), P < 0.001]. The moderate lifestyle (3–4 points) had an odds ratio of 0.619 for trouble sleeping [(95% CI: 0.501, 0.764), P < 0.001], while the optimal lifestyle had an odds ratio of 0.413 for trouble sleeping [(95% CI: 0.317, 0.537), P < 0.001]. Exploratory mediation analysis suggested that depression may partially explain the association between healthy lifestyle and sleep duration (mediation effect proportion: 34.23%, P = 0.027) and trouble sleeping (mediation effect proportion: 46.01%, P < 0.001). Subgroup and sensitivity analyses further confirmed the stable associations between healthy lifestyle, depression, and sleep status. Conclusions Healthy lifestyle is significantly associated with sleep status among U.S. adults. Depression may represent an important pathway between healthy lifestyle and sleep status. However, due to the cross-sectional design, causal conclusions cannot be drawn.