Periodontitis, periodontal inflammation, and mild cognitive impairment: A 5‐year cohort study

Identification of modifiable factors for mild cognitive impairment (MCI) is important since individuals with MCI are at a high risk of dementia and disability. Previous studies have suggested a potential association between periodontitis and cognitive impairment, but the results remain inconclusive. We designed a 5-year longitudinal study to explore the association between MCI and periodontitis and periodontal inflammation in older adults.This study included 179 community-dwelling dentate individuals (62 men and 117 women, average age: 80.1 years). A full-mouth periodontal examination at six sites per tooth was performed at baseline. Case definitions provided by the European Workshop in Periodontology Group C (EWP definition) and the Centers for Disease Control/American Academy of Periodontology (CDC/AAP definition) were used to define severe periodontitis. Additionally, the periodontal inflamed surface area (PISA), reflecting the amount of inflamed periodontal tissue, was calculated using clinical periodontal parameters. Follow-up cognitive examinations for MCI diagnosis were performed by neurologists 1, 2, 3, and 5 years after baseline. Odds ratios (ORs) for MCI according to the presence of periodontitis and periodontal inflammation at baseline were calculated using multilevel mixed-effects logistic regression.At baseline, 56.4% and 27.4% of the participants had severe periodontitis by the EWP and CDC/AAP definitions, respectively. After adjusting for follow-up period and other baseline health characteristics (age, sex, smoking status, educational level, physical activity level, obesity, depression, and diabetes), severe periodontitis by either definition was significantly associated with MCI (for the EWP definition: adjusted OR = 3.58, 95% confidence interval [CI] = 1.45-8.87; for the CDC/AAP definition: adjusted OR = 2.61, 95% CI = 1.08-6.28). Periodontal inflammation assessed by PISA was also significantly associated with a higher OR for MCI (adjusted OR = 1.05, 95% CI = 1.01-1.10, per 10-mm2 increase in PISA).Severe periodontitis and periodontal inflammation were associated with incident MCI among older community-dwelling men and women.