Edentulism and persistent activities of daily living disability: evidence from CHARLS with exploratory frailty mediation analyses

Edentulism has been linked to functional decline, but its association with persistent activities of daily living (ADL) disability remains unclear. This study examined the longitudinal association between edentulism and incident persistent ADL disability among middle-aged and older Chinese adults and explored the mediating role of physical frailty. Data were obtained from the China Health and Retirement Longitudinal Study (2011–2018). A total of 7,548 participants aged ≥ 45 years who were free of ADL disability at baseline were included. Edentulism was assessed by self-reported. Persistent ADL disability was defined as disability in any of six basic ADL items (dressing, bathing, self-feeding, transferring, toileting, and continence) reported in two consecutive follow-up waves. Logistic regression models were used to estimate associations between edentulism and persistent ADL disability as well as individual ADL domains. Mediation analyses quantified the proportion mediated by physical frailty. During up to 7 years of follow-up, 800 participants (10.60%) developed incident persistent ADL disability. In the fully adjusted model, edentulism was associated with higher odds of persistent ADL disability (OR 1.40, 95% CI: 1.08–1.80, p = 0.009). Domain-specific analyses showed significant associations with persistent bathing and self-feeding difficulty. Physical frailty accounted for 16.63% of the association between edentulism and persistent ADL disability and 13.91% for persistent bathing disability. Edentulism was associated with higher odds of persistent ADL disability among middle-aged and older Chinese adults. The observed associations with specific ADL domains, particularly bathing disability, highlight the potential relevance of edentulism as a marker of long-term functional vulnerability. Physical frailty statistically accounted for part of the observed association; however, these findings should be interpreted as exploratory and not as evidence of a causal mediation pathway.