Cross-sectional study of the factors associated with the number of teeth in middle-aged and older persons with intellectual disabilities.

BACKGROUND: We investigated the number of teeth in middle-aged and older individuals with intellectual disability and evaluated the related factors. METHODS: A questionnaire survey on oral health was administered to 604 persons over 40 years old with intellectual disabilities in Aichi Prefecture, Japan. The questionnaire designed for this study included items on diagnosis of disability, severity of intellectual disability and type of residence. As oral-health-related factors, the proxy-reported number of teeth, family dentist, regular dental check-ups, problems during dental treatment and tooth-brushing frequency were evaluated. A multinomial logistic regression analysis was performed using the proxy-reported number of teeth (≥20, 10-19 or 0-9) as the dependent variable, and the odds ratios (ORs) and 95% confidence intervals (CIs) of independent variables were calculated. In addition, linear regression analysis was performed using the proxy-reported number of teeth as the dependent variable. RESULTS: In the multivariate multinomial logistic regression analysis, age, diagnosis of disability and type of residence were significantly associated with having 10-19 versus ≥20 teeth. Participants with autism spectrum disorder had a significantly lower OR for 10-19 teeth compared with those with intellectual disability [OR (95% CI): 0.49 (0.22-1.08)]. Age, diagnosis of disability, regular dental check-ups and tooth-brushing frequency were significantly associated with having 0-9 versus ≥20teeth. Participants with Down syndrome had a significantly higher OR for 0-9 teeth compared with those with intellectual disability [OR (95% CI): 3.17 (1.09-9.23)]. The ORs for 0-9 teeth of participants who did not attend regular dental check-ups and who brushed their teeth 1 time/day compared with ≥3 times/day were significantly high, and the OR (95% CI) was 2.37 (1.06-5.30) and 4.76 (1.09-20.77), respectively. [Corrections made on 22 August 2022, after first online publication: in the previous sentence, "who attend" has been changed to "who did not attend".] In the multivariate linear regression analysis, age, diagnosis of disability and regular dental check-ups were significantly associated with the proxy-reported number of teeth. The proxy-reported number of teeth was -0.42 less with each 1-year increase in age. With autism spectrum disorder, the proxy-reported number of teeth was 0.74 more compared with intellectual disability. In Down syndrome, the proxy-reported number of teeth was -0.93 less compared with intellectual disability. The proxy-reported number of teeth was -2.12 less for those who did not have regular dental check-ups. CONCLUSIONS: The number of teeth in middle-aged and older individuals with intellectual disability was related to age and the type of disability. Regular dental visits may be effective at preventing tooth loss in middle-aged and older persons with intellectual disability.