Edentulism and risk of all-cause dementia and Alzheimer's disease: A competing risk analysis by cognitive status

Background Edentulism is an irreversible marker of severe oral disease and systemic disadvantage, yet robust epidemiological evidence linking edentulism to clinically diagnosed dementia remains limited. Objective This study uses clinically diagnosed dementia outcomes, accounting for the competing risk of death, and examines whether edentulism is associated with dementia risk differently, depending on baseline cognitive status. Methods We conducted a matched-cohort study using 2006–2020 Health and Retirement Study and linked Medicare claims data. Our sample included 2927 edentulous and 12,857 dentate older adults without baseline dementia. We used Coarsened Exact Matching to balance socioeconomic factors between edentulous and dentate participants. Fine-Gray competing risk models were used to estimate associations between edentulism and the risk of all-cause dementia (ACD) and Alzheimer's disease (AD), with analyses stratified by baseline cognition (normal cognition versus cognitive impairment, no dementia [CIND]). Results Edentulism was significantly associated with a 21% higher risk of ACD in the total cohort (subdistribution hazard ratio (sHR) 1.21; 95% CI 1.12–1.32), consistent across normal cognition (sHR 1.21; 95% CI, 1.07–1.36) and CIND (sHR 1.22; 95% CI, 1.04–1,43) groups. For AD, edentulism was associated with a 33% higher risk in the total cohort (sHR 1.33; 95% CI 1.10–1.62). This association was pronounced among cognitively normal individuals (sHR, 1.69; 95% CI, 1.26–2.28) but not CIND group (sHR 1.18; 95% CI 0.81–1.72). Conclusions Edentulism is independently associated with an increased risk of incident ACD, irrespective of baseline cognitive status. Its association with AD is specific to cognitively normal individuals, highlighting a potential window for oral health interventions in dementia prevention.