Periodontitis and Subgingival Plaque Microbiota Associated With Brain Grey Matter Volume and Cognitive Impairment

ABSTRACT Aim To explore if periodontitis and subgingival plaque microbiota have a relation with brain regional grey matter volume (rGMV) and their association with impaired cognition. Material and Methods Clinical periodontal data, subgingival plaque, cognitive test and brain MRI data were collected from 137 participants. rGMVs were compared among groups and subgroups with different periodontal conditions. Correlation analyses and multivariate linear regression were conducted to explore the relationship betweem rGMV, clinical periodontal indices, subgingival plaque microbiota and cognition. The random forest method was used to find the best model for cognition status prediction. Results There were significant differences in rGMV of the left calcarine fissure and the surrounding cortex, bilateral lingual, left inferior parietal marginal, left superior parietal, left lenticular nucleus pallidum, left posterior orbital gyrus, left cuneus and left middle frontal gyrus of orbital part among groups with different periodontal conditions. In whole and subgroup analyses, the major trends were the same: patients with severe periodontitis had smaller rGMV. The clinical indicators of periodontitis and the composition of the subgingival microbiota were associated with rGMV and impaired cognition. Further, cognitive prediction model accuracy was improved by adding periodontitis‐related information. Conclusions Subgingival plaque microbiota and periodontitis were associated with rGMV and cognitive decline.