Risk of dementia in patients with periodontitis and related protective factors: A nationwide retrospective cohort study.

AIM: We aimed to evaluate the long-term risk of dementia in patients with periodontitis and its associated factors. MATERIALS AND METHODS: Using Taiwan's National Health Insurance Database, we identified 56,018 patients aged >/=50 years with newly diagnosed periodontitis in 2000-2008. A cohort of 56,018 adults without periodontitis was selected for comparison, with matching by age and sex. Both cohorts were followed from 2000 to the end of 2013, and incident dementia was identified during the follow-up period. Adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of dementia associated with periodontitis were calculated in the multivariate regressions. RESULTS: Periodontitis was associated with dementia risk (HR: 1.79, 95% CI: 1.67-1.93), and the association between periodontitis and dementia risk was significant in men, women, and people aged more than 60 years. Among patients with periodontitis, the use of statins (HR: 0.78, 95% CI: 0.71-0.87), metformin (HR: 0.53, 95% CI: 0.44-0.62), and influenza vaccination (HR: 0.67, 95% CI: 0.61-0.74) were associated with a reduced risk of dementia, while diabetes, mental disorders, and stroke were major significant risk factors. CONCLUSIONS: Periodontitis was a risk factor for dementia, while the use of statins and metformin may reduce the risk of dementia.