Subgingival microbiome at different levels of cognition

Area of Science:

• Oral microbiology
• Neuroscience
• Gerontology

Background:

• Oral health and cognitive function may have a bidirectional relationship.
• Changes in oral microbiota composition are observed in individuals with cognitive decline.

Purpose of the Study:

• To characterize subgingival microbiota composition in relation to cognitive status.
• To identify specific bacterial taxa associated with cognitive decline.

Main Methods:

• Analysis of subgingival microbiota using 16S rRNA gene sequencing in two cohorts (MINOPAR and FINORAL).
• Cognitive assessment using the Mini Mental State Examination (MMSE).
• Oral examinations including probing pocket depth (PPD) and caries assessment.

Main Results:

• Microbial diversity showed a trend of difference between MMSE categories.
• Probing pocket depth and caries presence were key determinants of microbial changes.
• Abundances of 101 taxa correlated with MMSE scores; eight taxa remained significant after adjustments.
• Lachnospiraceae [XIV] family, genus, and species increased with decreasing MMSE scores.

Conclusions:

• Cognitive decline is associated with distinct alterations in oral microbiota composition.
• Impaired cognition correlates with poorer oral health and the presence of gut bacteria in the oral cavity.
• Oral health practices need special consideration in older adults to support cognitive health.