Longitudinal association between sleep duration and fall risk in middle-aged and older adults: A multiple mediation pathways analysis.

Background: Falls are a leading cause of injury and mortality in older adults, with a rapidly increasing burden in China (Zhang et al., 2022) [1]. Although short sleep duration has been linked to falls, evidence from large prospective studies remains limited, and potential mechanisms are not fully understood (Zhu et al., 2022; Zhang et al., 2025) [2,3]. Methods: We analyzed 11,476 participants aged ≥45 years from the China Health and Retirement Longitudinal Study (CHARLS, 2011-2018). Restricted cubic splines (RCS) were used to examine the non-linear association between sleep duration and fall risk. Cox proportional hazards models were applied to estimate the association between sleep duration and incident falls during follow-up. Multiple mediation analysis was conducted to quantify the mediating roles of physical function, chronic disease burden, cognitive function, and instrumental activities of daily living (IADL). Results: Short sleep duration (<6.5 h) was associated with a higher risk of incident falls (Adjusted HR = 1.14; 95% CI, 1.07-1.22; P < 0.001). RCS analyses suggested a non-linear relationship, with increased risk mainly at shorter sleep durations, while no significant association was observed at longer durations. Mediation analysis indicated that this association was partly explained by physical function (25.2%), chronic disease burden (14.2%), cognitive function (8.2%), and IADL dependence (5.4%). Conclusions: Short sleep duration (<6.5 h) was associated with an increased risk of falls among middle-aged and older adults in China. This association may be partly mediated by impaired physical function and greater chronic disease burden, underscoring the importance of incorporating sleep health into multifactorial fall-prevention strategies.