Association Between Intrinsic Capacity and Edentulism in Middle-Aged and Older Adults: A Longitudinal Cohort Study...

Intrinsic capacity (IC) serves as a fundamental concept for assessing an individual's comprehensive functional status. This study utilized data from the China Health and Retirement Longitudinal Study (CHARLS) to investigate the association between IC and edentulism among middle-aged and older adults.

Data were sourced from four waves (wave 2011, wave 2013, wave 2015, and wave 2018) of national surveys within CHARLS conducted between 2011 and 2018, culminating in the inclusion of 9110 participants aged 45 and older. IC was evaluated across five domains: cognition, locomotion, vitality, sensory function, and psychological capacity. Each domain was scored as preserved (1 point) or impaired (0 points), resulting in a total score ranging from 0 to 6, with higher scores reflecting better overall functional capacity. Edentulism was ascertained via self-report, with participants responding 'yes' to the question, 'Have you lost all your teeth?' Cox proportional hazards regression was employed to analyse the relationship between IC and edentulism. Additionally, restricted cubic splines (RCS) were used to explore potential non-linear associations. Subgroup analyses were conducted to evaluate interaction effects within different populations. An XGBoost model was utilized to identify key predictive variables and develop a nomogram for predicting the risk of edentulism.

After adjusting for multiple confounding factors, higher IC (6 points) was found to be significantly associated with a lower risk of edentulism compared to participants in the lowest IC category (scores 0-1) (HR = 0.609, 95% CI: 0.403-0.919, p = 0.018). When IC was dichotomized using a cut-off of > 5 points (intact vs. impaired), this association remained significant (HR = 0.876, 95% CI: 0.771-0.995, p = 0.041). RCS analysis further indicated a negative linear correlation between IC scores and the prevalence of edentulism. Subgroup analyses revealed no significant interactions for any examined covariates (all interaction p > 0.05). The nomogram developed from age, education level, sleep duration, IC, and residential area exhibited strong predictive capability.

Higher IC is associated with a reduced risk of edentulism in middle-aged and older adults. The nomogram created based on key predictors offers a valuable tool for predicting the risk of edentulism.