Site-specific pain, sleep duration, and depressive symptom trajectories among middle-aged and older Chinese adults with baseline depressive symptoms: A CHARLS-based longitudinal study.

BACKGROUND: Pain at specific anatomical sites and depressive symptoms commonly co-occur in middle-aged and older adults, but their longitudinal association and the potential role of sleep duration remain unclear. This study examined whether site-specific pain was associated with depressive symptom trajectory membership among Chinese adults with baseline depressive symptoms. METHODS: Data were drawn from the China Health and Retirement Longitudinal Study from 2011 to 2018. A total of 1047 adults aged ≥45 years with baseline depressive symptoms were included. Group-based trajectory modeling was used to identify depressive symptom trajectories. Multinomial logistic regression examined associations between pain at 15 anatomical sites and trajectory membership. Exploratory indirect-effect analyses with 2000 bootstrap samples estimated indirect effects through self-reported sleep duration. RESULTS: Three trajectories were identified: Mild-Stable (13.2%), Moderate-Increasing (57.5%), and High-Persistent (29.4%). Pain at several anatomical sites was associated with higher odds of unfavorable depressive symptom trajectories, with stronger associations for the High-Persistent trajectory. In fully adjusted models, the strongest associations with the Moderate-Increasing trajectory were observed for finger, wrist, arm, head, and neck pain, whereas head, arm, neck, toe, and stomach pain showed the strongest associations with the High-Persistent trajectory. Exploratory indirect-effect analyses suggested modest indirect effects through sleep duration for several pain sites, with the largest estimated indirect-effect proportion being approximately 8.9%. CONCLUSIONS: Site-specific pain was associated with unfavorable depressive symptom trajectories, particularly the High-Persistent trajectory. Sleep duration showed only modest exploratory indirect effects.