Objective: Evidence has reported gender differences in time of sleep, however, less is known whether this may have an impact on the association between sleep duration and risk of frailty. This study aims to explore gender differences in the association between sleep duration and frailty risk in Chinese adults.
Methods: 4,808 adults aged 45 years and over (52.8% females), participants in the China Health and Retirement Longitudinal Study (CHARLS) were followed up from 2011 to 2020. Sleep duration was self-reported (short <7h; normal 7-9h, long>9h). Frailty was determined using the 44-item deficit accumulation frailty index (FI); individuals with FI ≥0.25 were classified as frail. The association of sleep duration with frailty was explored by Cox proportional hazards regression models adjusted for demographic, socio-economic, behavioural factors and body mass index. Hazard ratios (HR) and 95% confidence intervals (Cis) were reported.
Results: Short, normal and long sleep duration was reported by 47.4%, 47.5% and 5.1% of women, and 47.5%, 48.3% and 4.2% of men respectively. There were 829 (17.2%) cases of frailty (63.9% in women and 36.1% in men) during a median follow-up of 9 years. After adjusting for confounders, women who reported long (HR = 1.34, 95% CI 1.09-1.64) and short sleep duration (HR = 1.73, 95% CI 1.57-1.91) had a higher risk of frailty, compared to those reporting normal sleep duration. Similarly, compared to men reporting normal sleep duration, higher risk of frailty was observed in men reporting long (38%, HR = 1.38, 95% CI 1.06-1.79) and short sleep duration (39%, HR = 1.39, 95% CI 1.21-1.60).
Conclusions: Shorter and longer sleep duration are associated with a higher risk of frailty in both men and women, however, shorter sleep duration may be more detrimental to women than it is for men putting them at a greater risk of frailty. Better understanding of gender difference in sleep patterning and its effect on frailty can help inform development of gender-specific interventions to reduce frailty and enhance healthy ageing.