# Oral microbiome diversity shapes the association between leisure-time physical activity and cognitive function among older adults

## TL;DR

This study finds that both physical activity and a diverse oral microbiome are linked to better cognitive function in older adults.

## Contribution

The novel contribution is identifying how physical activity and oral microbiome diversity jointly influence cognitive outcomes.

## Key findings

- Higher physical activity is associated with better memory and processing speed.
- Greater oral microbiome diversity is linked to improved processing speed.
- Combined physical activity and microbiome diversity are tied to better verbal fluency and processing speed.

## Abstract

Regular leisure-time physical activity and the composition of the oral microbiome may influence late-life cognition, but their combined effects are unclear. We studied 575 US adults aged 60–69 years from a nationally representative survey with oral microbiome sequencing, self-reported leisure-time physical activity, and four standard cognitive tests of memory, verbal fluency, and processing speed. Higher weekly physical activity and meeting current guideline levels were associated with better memory and processing speed scores after multivariable adjustment. Greater oral microbiome diversity, including higher richness and evenness, was also related to better processing speed. Among participants who met activity guidelines, those with intermediate to high Shannon diversity and a specific community composition profile showed the most favorable verbal fluency and processing speed. These findings suggest that maintaining both regular physical activity and a diverse oral microbiome may jointly support cognitive function in later life and promote healthy aging.

•Nationally representative study linking LTPA, oral microbiome, and cognition•Greater oral α-diversity is independently associated with better cognitive function•Physical activity-cognition link is stronger in diverse, commensal-rich communities•Findings support integrated lifestyle and oral health strategies for healthy aging

Nationally representative study linking LTPA, oral microbiome, and cognition

Greater oral α-diversity is independently associated with better cognitive function

Physical activity-cognition link is stronger in diverse, commensal-rich communities

Findings support integrated lifestyle and oral health strategies for healthy aging

Health informatics; Health sciences; Medical specialty; Medicine; Psychiatry