Utilization of Dental Care and the Incidence of Dementia: A Longitudinal Study of an Older Japanese Cohort.

Introduction: A relationship between periodontal disease and dementia has been reported. It is important to visit a dentist to maintain healthy periodontal tissue. Few studies have been reported on the association between dental visits and the risk of dementia. This study examined the relationship between the use of dental care among older people and the incidence of dementia based on health insurance claims data.

Materials and methods: We targeted 31,775 people aged 75 or 80 years. Dental utilization was obtained from the health insurance claims data from April 2014 to March 2015. The month when dementia medical costs were first incurred during the 4-year follow-up period was defined as the dementia onset month. Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of the incidence of dementia for the use of dental care.

Results: Regarding the type of dental visit, the adjusted HR of overall dementia was significantly lower (0.89: 95% CI, 0.81-0.98) in those who received periodontal treatment compared with those who did not receive any dental treatment. Regarding the days of periodontal treatment, participants with ≥5 days had significantly lower adjusted HRs for overall dementia, Alzheimer's disease, and vascular dementia than those with 0 days, and the adjusted HRs were 0.84 (95% CI, 0.75-0.94), 0.88 (95% CI, 0.77-1.00), and 0.82 (95% CI, 0.69-0.99), respectively.

Conclusion: Individuals who received periodontal treatment on many days had a low risk of dementia. Regular dental visits to treat or prevent periodontal disease may be important to prevent dementia.