[Association between masticatory function and mild cognitive impairment in middle-aged and older adults and mediating...

Objective: To explore the association between chewing dysfunction and the prevalence of mild cognitive impairment (MCI) among middle-aged and older adults in China, and to examine the mediating role of dietary patterns in this association. Methods: Participants aged ≥55 years with complete data on demographics, lifestyle, disease history, dietary surveys, anthropometric measurements, chewing function, and cognitive function were selected from the 2022-2023 China Health and Nutrition Survey. Dietary information was collected through three consecutive 24-hour dietary recalls combined with the household weighing and recording method, and dietary patterns were extracted using factor analysis. Chewing function was assessed using a self-reported scale evaluating the ability to chew eight common food items. Cognitive function was assessed using the Mini-Mental State Examination, and MCI was defined according to education-specific cutoff points. Multivariable logistic regression models were applied to analyze the association between chewing dysfunction and MCI, and mediating effect models were used to test the mediating role of dietary patterns. Results: A total of 2 407 participants were included. The prevalence of MCI and chewing dysfunction was 24.56% and 31.53%, respectively. After adjustment for potential confounders, chewing dysfunction was significantly associated with a higher likelihood of MCI (OR=2.08, 95%CI: 1.67-2.58). This association was modified by age and educational level: the strongest association was observed among individuals aged 55-59 years, and significant associations were identified among those with primary school education or below and those with junior middle school education. Four dietary patterns were identified by factor analysis: a southern pattern characterized by high intakes of rice and products, pork, and aquatic products; a northern pattern characterized by high intakes of vegetables and pork; a modern pattern characterized by high intakes of fruits, eggs, dairy products, and nuts; and a plant-based pattern characterized by high intakes of tubers, rice and products, and legumes products. The modern dietary pattern (mediating effect accounting for 3.98% of the total effect, P=0.023) played a significant mediating role in the association between chewing dysfunction and MCI. Specifically, chewing dysfunction reduced the intake of fruits, eggs, dairy products, and nuts, thereby potentially increasing the likelihood of MCI. Conclusions: Chewing dysfunction may increase the likelihood of MCI among middle-aged and older adults in China. The modern dietary pattern characterized by high intakes of fruits, eggs, dairy products, and nuts is an important mediator of this association, suggesting that maintaining good chewing function and optimizing dietary structure may be important strategies for preventing MCI in middle-aged and older adults.