Tooth loss is associated with mild memory impairment in the elderly: The Fujiwara-kyo study

It has been reported that tooth loss is associated with Alzheimer's disease (AD) and dementia. The purpose of this study was to investigate the association between tooth loss and mild memory impairment (MMI) among the elderly. We examined 3,061 community residents aged 65 years or older who had a score of 24 or more on the Mini-Mental State Examination. The subjects were divided according to their score for the three-word delayed recall test into control (score: 3 or 2) and MMI (score: 1 or 0) subjects. The subjects underwent a dental examination, an interview to determine their medical history, a self-administered questionnaire (inclusive of higher-level functional capacity, drinking and smoking habits, and frequency of going out), and a 10-m walking test. Fewer remaining teeth, going out once a week or less frequently, and a slow walking speed on a 10-m walking test were found at a significantly higher prevalence in the MMI group (n = 101) than in the control group (n = 2,960), after adjustment for sex, age, and the level of education. Multiple logistic regression analysis using these items revealed that the odds ratio of 0–10 remaining teeth for MMI was 1.71 (95% CI 1.05–2.78), compared to individuals with 22–32 remaining teeth. A significant increase was also found in a trend test to examine the increasing odds ratios of 22–32, 11–21, and 0–10 remaining teeth. We consider that tooth loss is associated with MMI later in life.

Research Highlights
► Approximately 40% of the subjects with MMI had 0–10 remaining teeth.
► The odds ratio for MMI was 1.71 (95% CI 1.05–2.78) (0–10/ 22–32 remaining teeth).
► These findings suggest that tooth loss is associated with MMI.