Association between Tooth Loss and the Development of Mild Memory Impairment in the Elderly: The Fujiwara-kyo Study

Background: Tooth loss may be a modifiable risk factor for memory disorders, but the causal relationship has not been evaluated sufficiently. Objective: This 5-year prospective cohort study investigated the effect of tooth loss on the development of mild memory impairment (MMI) among the elderly. Methods: Data are from the baseline and follow-up examinations of 2,335 community residents who were cognitively intact at baseline. The number of remaining teeth at baseline was classified as zero, 1-8, 9-16, 17-24, and 25-32. The main outcome for the analysis was the development of MMI at follow-up. Results: After adjustment for potential confounding factors in multivariable logistic regression analysis, the odds ratio of per 1 tooth loss at baseline was 1.02 (95% confidence interval, 1.00-1.03). The odds ratio of edentulism for MMI was 2.39 (1.48-3.86) compared to 25-32 teeth. The odds ratio of becoming edentulous compared to retaining 1-8 teeth in the 1-8 teeth group at baseline was 4.68 (1.50-14.58). Conclusion: Tooth loss predicts the development of MMI among the elderly.