Associations between edentulism and risk of neurodegenerative diseases among middle-aged and older adults in China: a decade-long cohort study

The important risk factor of edentulism provides a new perspective and entry point for the prevention of neurodegenerative diseases (NDs). Nevertheless, previous studies mostly focused on the short-term effects of a single factor and ignored the combined effects of long-term and multiple factors. We aim to comprehensively ascertain the impact of edentulism on the risk of NDs among middle-aged and older adults. We conducted a longitudinal analysis of respondent data from 2011 to 2020 in the China health and retirement longitudinal study (CHARLS) to investigate the association between the two. Propensity score matching (PSM) was used to reduce the effects of bias and confounding, and the Cox proportional hazards model was applied to evaluate the association between edentulism and risk of NDs. Among 10,851 respondents, incidence of NDs were 29.5% (2935/9942) among respondents without edentulism and 44.1% (401/909) among those with edentulism. After PSM, respondents with edentulism showed a higher risk of NDs (HR 1.24, 95% CI 1.07 to 1.45, P = 0.005) over time compared with traditional multivariable Cox analysis. Hearing impairment, heart disease and hypertension are important factors that exacerbate the progression of NDs. Sensitivity and subgroup analysis showed the results were still stable. A significant interaction (P for interaction = 0.030) was found between edentulism and age, particularly in the 45-64 age group. A comprehensive and targeted strategy for the 45-64 age group to practice good oral hygiene, combined with personalized management of specific health conditions, can be instrumental in preventing NDs.