The association between tooth loss and cognitive function in middle-aged and elderly people in China: A multiple mediation analysis based on the biopsychosocial model.

PURPOSE: This study investigated how tooth loss relates to cognitive function among Chinese middle-aged and older adults, with particular attention to whether nutritional status, depressive symptoms, and social engagement serve as mediating factors in this relationship. METHOD: Data were drawn from the 2015 wave of the China Health and Retirement Longitudinal Study (CHARLS), comprising 4,386 individuals aged 45 and above. A binary measure of complete tooth loss served as the indicator for dental status. The analysis considered three mediators: the triglyceride-total cholesterol-body weight index (TCBI), depressive symptoms as evaluated by the 10-item Center for Epidemiologic Studies Depression Scale (CESD-10), and a composite index of social engagement. Cognitive performance was quantified on a 0-21 scale encompassing two components: episodic memory and mental status. The R package lavaan was employed to build parallel multiple mediation models, with bootstrap procedures applied to evaluate indirect effects. RESULTS: A direct link was identified between tooth loss and diminished cognitive performance (β = 0.21, P < .001). Regarding the social engagement pathway, tooth loss predicted reduced engagement, which subsequently correlated with worse cognitive outcomes (β = 0.02, P < .010). For the nutritional pathway, tooth loss predicted lower TCBI values, which in turn were linked to diminished cognitive performance (β = 9.40 × 10-3, P < .001). The combined indirect pathways explained 14.2% of the overall effect (β = 3.40 × 10-2, P < .001). Although CESD-10-assessed depressive symptoms showed a correlation with cognitive function (r = .18, P < .001), they did not demonstrate a statistically significant mediating role (P = .125). CONCLUSION: Among Chinese middle-aged and older adults, tooth loss was linked to diminished cognitive performance. Both nutritional status and social engagement emerged as partial mediators of this relationship, while depressive symptoms failed to exhibit a noteworthy mediating influence. These results advocate for incorporating oral health care, nutritional evaluation, and social engagement facilitation into programs aimed at promoting cognitive well-being in aging individuals.