Tooth Loss and Decline in Functional Capacity: A Prospective Cohort Study from the Japan Gerontological Evaluation Study

Objectives To describe associations between tooth loss and changes in higher‐level functional capacity. Design Prospective cohort study. Setting Twenty‐four Japanese municipalities between 2010 and 2013. Participants Functionally independent community‐dwelling persons aged 65 and older (N = 62,333). Measurements Self‐reported number of teeth was used as an exposure variable. The outcome was changes in higher‐level functional capacity measured using the Tokyo Metropolitan Institute of Gerontology Index of Competence ( TMIG ‐ IC ), which consists of three domains: instrumental activities of daily living, intellectual activity, and social roles. The TMIG ‐ IC score ranges from 0 (lowest function) to 13 (highest function). All covariates were chosen from baseline demographic, socioeconomic, health behavior, and health variables based upon evidence from previous studies. Inverse‐probability weighting ( IPW ) with propensity score and multiple linear regression, estimating nonstandardized coefficients (β) and 95% confidence intervals (CIs), were used. Results The baseline response rate was 65.2%, and the follow‐up rate was 70.1%. During the follow‐up period, participants’ TMIG ‐ IC score declined by an average of 0.247 points (standard deviation: 1.446). The results showed a significant dose‐response association between tooth loss and decline in higher‐level functional capacity in multiple linear regression models. IPW models estimated the increment in TMIG ‐ IC score (β = 0.170, 95% CI = 0.114 to 0.227) if edentulous participants gained 20 or more natural teeth. Conclusion Tooth loss is associated with future decline in higher‐level functional capacity. IPW models suggest that treatment for tooth loss attenuates decline in higher‐level functional capacity.