Oral health condition of French elderly and risk of dementia: a longitudinal cohort study

Abstract

Objectives: Oral condition could be associated with cognitive impairment, but this is not yet well documented. We therefore hypothesized that people with poor oral condition would be more at risk to develop dementia. The objective of this study thus was to describe the oral condition of French community-dwelling elderly persons and to assess its relationship with the occurrence of dementia.

Methods: Oral examination was conducted on a sample of individuals aged 66-80 years followed-up prospectively for screening of dementia over 15 years in Gironde, France. Univariate and multivariate analyses of the risk of dementia were performed using a Cox proportional hazard model with delayed entry.

Results: Data from 405 individuals were analyzed; 45.4% men; median age at baseline: 70 years [interquartile range (IQR): 68-75]. The median number of decayed, missing, and filled teeth was 18 (IQR: 13-24) and was higher in women (median: 20 versus 17, P = 0.004) and in persons with lower school level (median: 21 versus 17, P = 0.003). Among 348 persons with sextant eligible for periodontal assessment, 2/3 required periodontal care: 5.2% had bleeding observed, 44.8% calculus, 17.8% 4-5 mm pockets, and 2.9%≥ 6 mm pockets. The incidence of dementia during a median follow-up of 10 years (IQR: 6.5-13.7) was 19 per 1000 person-years. The adjusted hazard ratio for a number of missing teeth ≥ 11 (median) on the risk of dementia was 1.13 (95% confidence interval, CI = [0.60-2.12]) in people with higher education (n = 312) and 0.30 (CI = 0.11-0.79) in persons with lower school level (n = 93) (P for modification effect = 0.0002).

Conclusions: Having eleven or more missing teeth seemed to be associated with a lower risk of dementia in people with lower education possibly owing to the suppression of source of chronic inflammation.