The link of oral microbiome diversity to stroke risk: evidence from the national cohort study in the United States.

OBJECTIVE

To assess whether oral microbiome diversity and periodontal health are independently associated with stroke prevalence in a U.S. adult cohort, with implications for risk stratification in physical medicine and rehabilitation.

METHODS

We analyzed cross-sectional NHANES 2009-2012 data from 4,438 adults. Survey-weighted logistic regression estimated associations of stroke with oral microbiome β-diversity (unweighted UniFrac), α-diversity (Shannon and Simpson), and periodontal measures (probing depth, attachment loss, tooth count), adjusting for demographic, socioeconomic, behavioral, and cardiometabolic covariates.

RESULTS

In crude models, each 1-mm increase in probing depth (odds ratio [OR] 1.89, 95% CI 1.39-2.56) and attachment loss (OR 1.50, 95% CI 1.32-1.71) raised stroke odds; each additional tooth lowered them (OR 0.91, 95% CI 0.88-0.94). After stepwise adjustment, attachment loss (OR 1.23, 95% CI 1.04-1.46; P=0.017) and tooth count (OR 0.96, 95% CI 0.92-0.99; P=0.024) remained significant, whereas probing depth did not (OR 1.30, 95% CI 0.90-1.88; P=0.156), with a threshold near 1.46 mm. β-Diversity clusters did not differ after adjustment (global P=0.61), and neither α-diversity index was significant (Shannon fully adjusted OR 1.29, 95% CI 0.97-1.72; P=0.081). Periodontal associations were consistent across sex and age strata; null findings in younger participants reflected limited power.

CONCLUSION

Attachment loss and tooth count were associated with stroke prevalence independently of traditional risk factors, whereas microbiome diversity indices were not. These measures may help refine risk assessment. The cross-sectional design precludes causal inference, and prospective cohorts with adjudicated outcomes and metagenomic profiling are needed.