Oral microbiome and Frailty: Insights from NHANES 2009-2012 and Mendelian Randomization Analysis

Area of Science:

• Gerontology
• Microbiology
• Genetics

Background:

• Frailty is a significant health concern linked to adverse outcomes like disability and mortality.
• The oral microbiome's role in frailty is suggested but lacks robust population-based evidence and causal validation.

Purpose of the Study:

• To investigate the association between oral microbiome diversity and frailty in a U.S. adult population.
• To explore potential causal relationships between specific oral bacteria and frailty using genetic methods.

Main Methods:

• Analysis of data from 2,696 U.S. adults aged ≥50 years (NHANES 2009-2012).
• Assessment of oral microbiome diversity (α- and β-diversity) via 16S rRNA gene sequencing.
• Frailty measured using a 36-item Frailty Index.
• Bidirectional two-sample Mendelian randomization (MR) applied to GWAS data to infer causality.

Main Results:

• Lower oral microbiome α-diversity was significantly associated with higher frailty scores.
• Distinct oral microbiome β-diversity patterns were observed between frail and non-frail individuals.
• MR analyses identified specific oral taxa with potential protective (e.g., Campylobacter_A, TM7x) or risk (e.g., Gemella) effects on frailty.

Conclusions:

• Oral microbiome diversity is inversely associated with frailty in U.S. adults.
• Specific oral bacterial taxa may causally influence frailty development.
• The oral microbiome represents a potential modifiable target for promoting healthy aging.