Mediating effect of social frailty on oral frailty and cognitive function in older adults: a cross-sectional study in a rural Chinese community

Abstract

Cognitive function has been associated with both social and oral frailty. However, few studies have explored how social frailty and oral frailty jointly relate to cognitive function. This study aimed to explore whether social frailty plays a mediating role in the association between oral frailty and cognitive function and to examine potential gender differences in this pathway. This was a cross-sectional study design, and the data were obtained from the 2022 follow-up survey of the Health Status of Rural Older Adults (HSRO). The Mini-Mental State Examination (MMSE) was used to assess cognitive function, the Tanaka’s Oral Frailty Index-8 (OFI-8) was used to assess the risk of oral frailty, and social frailty was assessed using an operational definition that included five items: going out less frequently, rarely visiting friends, feeling unhelpful to friends or family, living alone, and not talking with someone every day. Statistical analyses were performed using hierarchical multiple linear regression analysis and Hayes’ PROCESS version 4.1 for mediation analysis in SPSS (IBM, Armonk, NY, United States). Oral frailty, social frailty, and cognitive function were significantly related ( p < 0.05). After adjusting for potential confounding variables, oral frailty and social frailty were negatively associated with cognitive function. The total effect of oral frailty on cognitive function was −0.089 (95% CI: −0.206, 0.028), and the indirect effect mediated by social frailty was −0.067 (95% CI: −0.103, −0.034), while the direct effect value was −0.022 (95% CI: −0.143, 0.098). The proportion of the indirect effect was 75%. In older men, the total effect of oral frailty on cognitive function was −0.206 (95% CI: −0.389, −0.024), and the indirect effect mediated by social frailty was −0.062 (95% CI: −0.119, −0.016). In older women, the total effect of oral frailty on cognitive function was not statistically significant, whereas the indirect effect through social frailty was −0.075 (95% CI: −0.139, −0.031). This cross-sectional study suggests that social frailty may mediate the association between oral frailty and cognitive function, providing statistical evidence of an association among these three factors. However, further prospective longitudinal studies are needed to validate these findings.