Edentulism and incident hip fracture among middle-aged and older adults in China: evidence from the CHARLS

BACKGROUND: Hip fractures are a major cause of disability and mortality in aging populations, yet risk prediction based solely on traditional clinical factors remains limited. Edentulism is prevalent in later life and may reflect broader systemic vulnerability through pathways involving impaired nutrition, functional decline, and frailty. However, longitudinal evidence linking edentulism to hip fracture risk remains limited. This study examined the association between edentulism and incident hip fracture and explored whether frailty might represent a potential pathway. METHODS: Data were obtained from the China Health and Retirement Longitudinal Study, a nationally representative cohort of Chinese adults. A total of 7,385 community-dwelling participants aged ≥ 45 years without prior hip fracture at baseline (2011) were followed through 2020. Baseline edentulism was self-reported, and incident hip fracture was defined as the first report during follow-up. Associations were estimated using multivariable Cox proportional hazards models. Frailty, assessed using a frailty index, was evaluated in exploratory mediation analyses as a potential pathway. Subgroup and sensitivity analyses, including temporally ordered analyses of frailty, were conducted to assess robustness. RESULTS: Over up to 9 years of follow-up, 313 participants (4.24%) experienced a first hip fracture. In fully adjusted models, edentulism was associated with a higher risk of incident hip fracture (hazard ratio 1.55, 95% CI: 1.08-2.20, p = 0.016). Kaplan-Meier analyses showed a significantly higher cumulative incidence of hip fracture among edentulous individuals (log-rank p < 0.001). Exploratory mediation analyses were consistent with frailty as a potential pathway underlying the observed association, with an estimated indirect effect corresponding to 9.2% of the total association. The findings were robust across subgroup and sensitivity analyses. CONCLUSIONS: Edentulism was associated with an elevated risk of hip fracture among middle-aged and older adults in China. Exploratory analyses were consistent with frailty as a potential pathway underlying this association, although causality cannot be established. Dentition status may inform targeted strategies for identifying individuals at heightened hip fracture risk, guiding interventions such as frailty assessment, nutritional support, fall prevention, and integrated oral health management.