Association between the number of remaining teeth and disability-free life expectancy, and the impact of oral self-care in older Japanese adults: a prospective cohort study.

ABSTRACT

BACKGROUND: Tooth loss has been reportedly associated with shorter disability-free life expectancy (DFLE). However, no study has explored whether oral self-care offsets reduction in DFLE. The present study aimed to assess the association between oral self-care and DFLE in older individuals with tooth loss. METHODS: Data on the 13-year follow-up from a cohort study of 14,206 older Japanese adults aged ≥ 65 years in 2006 were analyzed. Information on the number of remaining teeth was collected using a questionnaire, and the participants were then categorized into three groups (0-9, 10-19, and ≥ 20 teeth). Additionally, "0-9" and "10-19" groups were divided into two subgroups based on whether they practiced oral self-care. DFLE was defined as the average number of years a person could expect to live without disability, and was calculated by the multistate life table method based on a Markov model. RESULTS: DFLE (95% confidence interval) was 19.0 years (18.7-19.4) for 0-9 teeth, 20.1 (19.7-20.5) for 10-19 teeth, and 21.6 (21.2-21.9) for ≥ 20 teeth for men. For women, DFLE was 22.6 (22.3-22.9), 23.5 (23.1-23.8), and 24.7 (24.3-25.1), respectively. Practicing oral self-care was associated with longer DFLE, by 1.6-1.9 years with brushing ≥ 2 times a day in people with 0-9 and 10-19 teeth, and by 3.0-3.1 years with the use of dentures in those with 0-9 teeth. CONCLUSIONS: Practicing oral self-care is associated with an increase in DFLE in older people with tooth loss.