Periodontal disease and dementia risk: A narrative review of population-based evidence and modifiable interventions

Abstract

Dementia affects over 50 million people worldwide and is projected to triple by 2050. Chronic inflammation and microbial dysbiosis, including periodontal disease, may contribute to neurodegenerative disease development. We reviewed eight population-based studies from Taiwan (matched-cohort, prospective, and retrospective designs) that examined periodontal exposures (tooth loss, chronic periodontitis, and gingivitis) in relation to dementia or cognitive impairment, with multivariable adjustment for confounders. Periodontal disease was consistently associated with increased dementia risk (unadjusted hazard risk [HR] up to 1.79; adjusted HR = 1.16, 95% confidence interval = 1.01–1.32). Tooth loss and absence of denture use also predicted cognitive decline. Among patients with periodontitis, protective factors included statins (HR = 0.78), metformin (HR = 0.53), and influenza vaccination (HR = 0.67). Comorbidities such as diabetes, mental disorders, and stroke further amplify dementia risk. These findings support periodontal disease as a modifiable risk factor for dementia. Integrating periodontal treatment, metabolic and immunomodulatory therapies, and prosthetic rehabilitation may help reduce dementia risk. Randomized trials with standardized oral assessments, biomarkers, and cognitive measures are needed to establish causality and guide preventive strategies.