Oral Frailty, Social Frailty, and 6-Year Risk of Long-term Care Onset

OBJECTIVES: This 6-y longitudinal study examined the relationship between oral frailty measured in 2016 and the onset of long-term care (LTC) measured in 2022 and investigated whether social frailty (SF) measured in 2019 mediates the association among community-dwelling older adults aged ≥65 y in Japan. METHODS: Four waves (2013-2022) of data from the Japan Gerontological Evaluation Study (JAGES) were analyzed. Oral frailty was classified into robust, pre-oral frail, and oral frail categories. LTC onset was identified through official certification records. Logistic regression models estimated odds ratios (ORs) for LTC onset after adjusting for sociodemographic, behavioral, and health-related confounders measured in 2013. Causal mediation analysis using parametric logistic regression models was used to assess social frailty (robust and social frail) as a mediating pathway. RESULTS: During 6 y of follow-up among 3,559 participants (48.7% males, mean [SD] age 71.9 [4.8]), 6.1% developed LTC dependency. Overall, a clear gradient relationship was observed. The oral frail group had a 47% likelihood of enrolling in LTC compared with the robust group (adjusted OR = 1.47; 95% confidence interval [CI], 1.01-2.17), while the pre-oral frail group was 39% more likely to enroll in LTC (adjusted OR = 1.39; 95% CI, 0.96-2.02) than the robust group. Furthermore, SF mediated approximately 7% to 19% of the association between oral frailty and LTC onset, indicating that declining oral function contributes to social vulnerability, which in turn accelerates the dependency. Moreover, sensitivity analysis restricted to a complete data scenario attenuated the relationship, likely due to reduced power and missing data. CONCLUSION: These findings suggest that oral frailty may be an important predictor of long-term care onset, with part of the association potentially explained by social frailty. Maintaining oral health and promoting social participation may be important components of strategies aimed at supporting healthy aging and potentially reducing the risk of care dependency.Knowledge Transfer Statement:This longitudinal cohort study shows that oral frailty increased the risk of long-term care dependency among older adults after 6 years, partly through social frailty. For patients and clinicians, maintaining natural dentition and oral function might help preserve social engagement and delay care dependency. For policymakers, these findings could guide the provision of oral health initiatives, such as integrating oral health promotion and social participation strategies into healthy aging and long-term care prevention policies.