Associations between sleep duration and quality and physical frailty in community-dwelling older adults: a cross-sectional study

The effects of sleep duration and quality on physical frailty may differ. We examined the association between sleep duration/quality and frailty phenotype according to frailty components. This cross-sectional study analyzed 848 community-dwelling Japanese adults aged 65–75 years (mean age 70.8 yrs, 50.1% women) without long-term care needs. We classified the participants by their sleep duration: short-, middle-, and long-sleep groups. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI) and divided into PSQI ≤ 5, 6–8, and ≥ 9 groups. Physical frailty was operationalized with the Fried phenotype. A logistic regression model was used to compute the odds ratios (ORs) and 95% confidence interval (CIs) for frailty status outcomes. The prevalence of frailty was 4.7%. The ORs for the presence of frailty in the long-sleep group was 8.50 (95%CI: 2.82–25.62) compared to the middle-sleep group, and the PSQI ≥ 9 group was 2.81 (95%CI: 1.08–7.33) compared to the PSQI ≤ 5 group. Short sleep and poor sleep quality were associated with exhaustion; long sleep was associated with low physical activity. The duration and quality of sleep may thus have different effects on frailty components. The possible causal relationship between sleep duration/quality and frailty merits further investigation.