To explore the relationship between tooth loss and cognitive level in the elderly, and to verify the mediating roles of dietary diversity and social participation.

This paper used the data from the Chinese Longitudinal Healthy Longevity Survey (CLHLS) in 2018, and screened out 5 774 eligible research subjects. Spearman correlation analysis was used to explore the correlations among tooth loss, dietary diversity, social participation and cognitive level in the elderly.The chain mediating effects of dietary diversity and social participation between tooth loss and cognitive level in the elderly were analyzed using Model 6 of the Process 4.1 add-in in SPSS.

The direct effect of tooth loss on cognitive level in the elderly was significant (β=-0.298, P<0.01). Dietary diversity and social participation significantly influenced the cognitive level of the elderly (β=0.059, P<0.05; β=0.063, P<0.01). The mediating effects of dietary diversity and social participation between tooth loss and cognitive level in the elderly were -0.016 (95% CI: -0.005~-0.030) and -0.04 (95% CI: -0.016~-0.065), respectively, and the chain mediating effect was -0.011 (95% CI: -0.006~-0.017).

Tooth loss in older adults can directly affect their cognitive level, and can also influence cognitive function through the independent or chain mediating effects of dietary diversity and social participation. In the future, attention should be paid to the tooth loss situation of older adults, and their nutritional intake and social participation should be ensured to reduce the risk of cognitive impairment and achieve healthy aging.