Differential Associations of Oral Health with Early- and Late-Onset Dementia: A Prospective Analysis of the UK Biobank

Background Poor oral health is a modifiable risk factor for dementia, but whether the associations differ by age at onset and are modified by genetic susceptibility remains unclear. Methods In this prospective cohort study of 364,231 dementia-free UK Biobank participants, we examined associations between oral health indicators and incident early- and late-onset dementia (EOD and LOD). Genetic susceptibility was assessed using polygenic risk score (PRS) and apolipoprotein E (APOE) ε4 status. Multivariable Cox proportional hazards models evaluated independent and joint associations. Results Over a median follow-up of 13.6 years, 359 participants developed EOD and 6,668 developed LOD. Oral health indicators were not consistently associated with EOD. In contrast, painful gums (hazard ratio [HR], 1.24; 95% CI, 1.09–1.40), toothache (HR, 1.17; 95% CI, 1.04–1.33), denture use (HR, 1.18; 95% CI, 1.12–1.25), and a higher number of oral health conditions (HR, 1.08; 95% CI, 1.05–1.12) were consistently associated with increased LOD risk. Joint analyses demonstrated dose–response patterns for LOD, with the highest risks among individuals with both poor oral health and elevated genetic susceptibility. Conclusions Poor oral health was associated primarily with LOD, particularly among individuals with elevated genetic susceptibility.