Cognitive impairment and dementia represent global health challenges influenced by genetic predisposition and lifestyle factors. Epidemiological evidence supports an association between oral health and cognitive outcomes, with periodontal status and microbial dysregulation as a central component of this relationship. In a large community-based cross-sectional study, periodontal status and salivary microbiome composition showed clear connections with cognitive performance. Individuals with worse periodontal indicators, such as severe periodontitis, tended to have lower cognitive scores, suggesting that chronic oral inflammation may influence brain functions. Salivary microbiome profiling revealed coordinated shifts in microbial communities across periodontal and cognitive states. Worsening periodontal health was accompanied by increased microbial richness and enrichment of classic anaerobic pathogens, including Porphyromonas gingivalis, Treponema denticola, and other pro‑inflammatory taxa. Mediation analysis identified eleven microbial features that partially explained the relationship between periodontal inflammation and cognitive decline, pointing to biologically meaningful links along the oral–brain axis. Overall, the findings suggested that maintaining oral health may offer opportunities for early prevention and intervention in cognitive decline.
Suggested by Prof. Simonetta D’Ercole