To assess the interaction of dynapenic abdominal obesity (DAO) and sleep duration on the risk of functional disability among middle-aged and older Chinese individuals.

Data were extracted from the China Health and Retirement Longitudinal Study conducted in 2011, 2013, 2015, 2018, and 2020. A total of 6,343 participants were enrolled in this retrospective cohort study. Sleep duration was obtained through face-to-face interviews. Dynapenia (D) and abdominal obesity (AO) were defined by handgrip strength and waist circumference, respectively. Functional disability was assessed according to activities of daily living scales. Cox proportional hazard models analyzed the interactions of DAO and sleep duration on functional disability.

Over a mean follow-up of 10 years, 3,879 (61.2%) participants reported functional disability. Individuals with short sleep duration and D/AO (appropriate but short: RR = 1.42, 95% CI = 1.10–1.82, too short sleep: RR = 1.54, 95% CI = 1.16–2.06), long sleep duration and D/AO (appropriate but long: RR = 1.61, 95% CI = 1.11–2.33; too long: RR = 1.63, 95% CI = 1.15–2.32), were more likely to develop functional disability than those with normal sleep duration and ND/NAO in the fully adjusted model. The multiplicative interaction between the short sleep group and D/NAO or ND/AO were both significant. Middle-aged individuals and females were more susceptible to the effects of short sleep and DAO, while elderly individuals and males were more susceptible to the effects of long sleep and DAO.

Short and long sleep durations combined with DAO increase the risk of functional disability. Managing waist circumference and improving grip strength in middle-aged and older adults with abnormal sleep durations may help prevent functional disability.