Sleep Duration and Frailty Risk among Older Adults: Evidence from a Retrospective, Population-Based Cohort Study

OBJECTIVES: Frailty and sleep duration complaints are both prevalent and often coexist among older adults. The purpose of this study was to examine the prospective association between sleep duration and frailty risk in a nationally representative cohort study. DESIGN: Prospective cohort study, ten-year follow-up. SETTING: Community-based setting in 23 provinces of China. PARTICIPANTS: A total of 7623 older adults age 65 and over without frailty at baseline were included in the analysis. MEASUREMENTS: The participants were divided into three groups according to self-reported sleep duration: short (≤6 hours per day), middle (>6 but <10 hours per day) and long (≥10 hours per day). Frailty was measured according to the accumulation of health deficits by the construction of a frailty index of 38 items with 0.25 as the cutoff. A Cox proportional hazard model, a competing risk model and a generalized estimating equation (GEE) model with multiple adjustments were performed to evaluate the association between sleep duration and frailty risk. RESULTS: During a median follow-up period of 4.4 years (IQR 2.9-9.0), 2531 (33.2%) individuals developed frailty. Compared with participants with middle sleep duration, the risk of frailty was increased among participants with long sleep duration (HR 1.26, 95% CI 1.14-1.38) in the fully adjusted Cox proportional hazard model. However, short sleep duration was insignificantly associated with frailty risk. The competing risk model and the GEE model yielded similar results. CONCLUSION: Long sleep duration is significantly associated with frailty incidence among older adults even after adjustment for confounding factors. This study provides reinforcing longitudinal evidence for the need to design sleep quality improvement interventions in health care programs to prevent frailty among older adults.