Abstract
AIM: Chronic diseases accumulation and late-life depressive symptoms are prevalent health problems among older adults. This study aimed to investigate the association between them and examine the effect of sleep duration in this association. METHODS: The study included 6527 respondents. Hierarchical regression was used to examine the association between chronic diseases accumulation and late-life depressive symptoms, as well as the moderating effect of sleep duration. The simple slope test and the Johnson-Neyman plot were used to present how the aforementioned association varies under different sleep duration conditions. Placebo tests and adjustment test were carried out to validate the robustness of the results. RESULTS: Hierarchical regression results showed that chronic diseases accumulation is positively associated with late-life depressive symptoms (B = 0.272, P < 0.001), whereas sleep duration is negatively associated with late-life depressive symptoms (B = -0.443, P < 0.001) and plays a negative moderating effect (B = -0.050, P = 0.001). The simple slope test showed that the association between chronic diseases accumulation and late-life depressive symptoms at a low sleep duration level was stronger than that at a high level (low: B = 0.372, P < 0.001, high: B = 0.172, P = 0.001). The Johnson-Neyman plot showed that this association gradually decreased with the increase of sleep duration, and became non-significant when sleep duration exceeded 8.949 h. CONCLUSIONS: This study shows that there is a positive association between chronic diseases accumulation and depressive symptoms in older adults. This association becomes weaker with increased sleep duration, and is no longer statistically significant when sleep duration exceeds 8.949 h. Geriatr Gerontol Int 2025; 25: 879-888.