The association between sleep duration and risk of frailty: a prospective cohort study

Longitudinal evidence on the relationship between sleep duration and frailty in middle-aged and older adults remains limited. This study followed 18,282 middle-aged and older adults participating in the China Health and Retirement Longitudinal Study (2011–2020) to examine this association. Self-reported sleep duration was classified as short (<7 h), optimal (7–9 h), or long (>9 h). Frailty was defined using a 44-item frailty index (FI ≥ 0.25 indicating frailty). During a median 8.9-year follow‑up, 2125 participants (11.6%) developed frailty. Compared with optimal sleep duration, short (OR = 2.05, 95% CI 1.85, 2.27) and long sleep duration (OR = 1.45, 95% CI 1.16, 1.83) were associated with higher odds of frailty. The relationship was U-shaped, with the lowest odds of frailty observed at 7.1 h of sleep and an apparent optimal range of approximately 7–8 h. These findings support the potential importance of maintaining adequate sleep duration as part of frailty prevention strategies.