Number of remaining teeth and frailty in community-dwelling older adults: an exploratory analysis of the potential mediating role of oral health-related quality of life

Objectives Previous studies have indicated associations between the number of remaining teeth, oral health-related quality of life (OHRQoL), and frailty. We aimed to investigate the association between number of remaining natural teeth and frailty among Chinese community-dwelling older adults in Shanghai, and to explore whether OHRQoL mediates this association. Methods In this cross-sectional study, 1,122 Chinese community-dwelling older adults in Huangpu District, Shanghai, underwent oral examinations and completed questionnaires. Oral examinations were conducted according to the World Health Organization's Basic Methods for Oral Health Surveys (5th edition). Frailty was assessed using the FRAIL scale, and OHRQoL was measured with the Chinese version of Oral Health Impact Profile-14 (OHIP-14). A counterfactual-based causal mediation analysis with 5,000 bootstrap resamples was performed, using the three-category frailty outcome (robust/pre-frail/frail), to evaluate the mediating role of OHRQoL in the association between number of remaining teeth and frailty. Results Among the 1,122 participants, 225 were diagnosed with frailty, accounting for 20.05% of the participants. Age, sex, education, body mass index, and number of remaining teeth significantly differed between participants with and without frailty ( P < 0.01). After adjusting the covariates, logistic regression models showed that OHRQoL was significantly associated with frailty, with odds ratio (OR) = 1.140 [95% confidence interval (CI) 1.109–1.171]. In an exploratory analysis, OHRQoL was statistically consistent with a potential partial mediating role (proportion mediated = 19.3%, 95% CI 11.6%–31.2%). Conclusions There is a potential association between number of remaining teeth and frailty, and OHRQoL may play a partial mediating role in this relationship. Given the cross-sectional design, causal inference requires longitudinal confirmation. Oral health—particularly, the number of remaining teeth—should be a key focus for both the elderly and healthcare providers.