Sleep Duration and Mental Well-Being Among Older Chinese Adults: A Four-Wave Fixed-Effects Analysis Using CHARLS

Objectives To examine within-person associations between nighttime sleep duration and mental well-being among older Chinese adults.Methods We analyzed four waves of the China Health and Retirement Longitudinal Study (CHARLS; 2011–2018) using individual fixed-effects linear regressions with wave fixed effects and individual-clustered standard errors. Outcomes were CES-D-10 depressive symptoms and reverse-coded life satisfaction. Sleep was modeled continuously and categorically, with main categories of ≤6 h, >6 to <9 h, and ≥9 h; sensitivity models used ≤ 5 h, >5 to <9 h, and ≥9 h.Results Among observations with valid CES-D-10 data, 36.74% met the ≥10 screening threshold. Each additional hour of sleep was associated with lower CES-D-10 scores (β = −0.305) and higher life satisfaction (β = 0.015). Compared with the main reference range, short sleep was associated with higher CES-D-10 scores (β = 0.846) and lower life satisfaction (β = −0.046). Long-sleep estimates varied by specification and outcome.Conclusions Shorter nighttime sleep duration, particularly sleep in the operational short-sleep category, was associated with poorer mental well-being within individuals over time.Clinical implications Usual sleep duration can inform mood and sleep assessment but should not substitute for evaluation of sleep quality or sleep disorders.