The Relationship Between Oral Health and Cognitive Function Among Community‐Dwelling Japanese Older Adults: A Cross-sectional Study Using Toon Health Study Data

Abstract

Abstract Background This study aimed to investigate the relationship between tooth loss and cognitive function in community-dwelling elderly. Methods A total of 438 men and 715 women aged 60–84 years who participated in the Toon Study—an epidemiological study conducted among local residents of Toon City, Ehime Prefecture, Japan from 2014 to 2018—were included. A self-administered questionnaire was used to assess oral health status (number and bite of teeth). Mild cognitive impairment (MCI) was assessed using the Japanese version of the Montreal Cognitive Assessment, with scores < 26 considered as MCI. The odds ratios (OR) and 95% confidence intervals (95% CI) of MCI were compared with having 25 + teeth and good masticatory status, after adjusting for age, sex, and other potential confounding factors using a logistic regression model. Results The multivariate adjusted ORs (95% CIs) of MCI for having < 15 teeth compared with ≥ 25 was 1.34 (0.97–1.84). Additionally, that of poor masticatory performance compared with good masticatory status was 1.41 (1.06–1.88). Associations were evident in those aged < 75, with ORs (95% CIs) for number of teeth and masticatory status of 1.58 (1.10–2.27) and 1.50 (1.09–2.08), respectively. This was in contrast to those aged ≥ 75 years. Conclusions Our findings suggest that, to maintain cognitive function, maintaining both the number of teeth and the complex oral function of bite in individuals aged < 75 years is vital.