Genus-level oral microbiome composition and Dietary Approaches to Stop Hypertension dietary adherence in relation to hypertension

BACKGROUND: Hypertension (HTN) remains a leading global health burden and a key risk factor for cardiovascular disease. While the Dietary Approaches to Stop Hypertension (DASH) diet is an established strategy for blood pressure control, the interplay between dietary patterns and the oral microbiome in the etiology of HTN is not well understood. OBJECTIVE: To investigate the independent and joint associations of genus-level oral microbiome composition and adherence to the DASH diet with hypertension in a nationally representative sample of US adults. METHODS: We analyzed data from the 2009-2010 and 2011-2012 National Health and Nutrition Examination Survey (NHANES), including 5371 adults with complete oral microbiome, dietary, blood pressure, and covariate data. Genus-level oral microbiome profiles were derived from oral rinse samples using 16S rRNA sequencing and transformed with the centered log-ratio method. DASH adherence was assessed from 24-h dietary recalls using a validated score. Hypertension was defined as self-reported diagnosis, antihypertensive medication use, or measured blood pressure meeting 2017 American College of Cardiology/American Heart Association (ACC/AHA) criteria (systolic ≥130 mmHg or diastolic ≥80 mmHg). Analyses employed a multistage design: differential abundance testing to identify hypertension-associated genera; survey-weighted multivariable logistic regression to examine independent and joint associations, adjusting for demographic, lifestyle, and clinical covariates; subgroup analyses by sex, age, and microbial characteristics; and sensitivity analyses to assess robustness. RESULTS: Greater adherence to the DASH diet was associated with lower odds of hypertension [high vs. low tertile odds ratio (OR) ≈0.62; P < 0.005]. Several oral bacterial genera - Actinomyces, Rothia, Lactobacillus, and Veillonella - showed independent associations with increased hypertension risk (OR range: 1.302-1.468; P < 0.05). Higher Faith's Phylogenetic Diversity was inversely associated with hypertension (OR = 0.742; P = 0.037). Stratified analyses suggested effect modification: the protective DASH-hypertension association was strongest among individuals with low Lactobacillus abundance and intermediate microbial diversity and Rothia abundance, more pronounced in women, and attenuated in adults aged at least 60 years. Sensitivity analyses confirmed these patterns, highlighting the consistent risk associated with Actinomyces and the stability of joint DASH-microbiome associations. CONCLUSION: Genus-level oral microbiome composition and DASH dietary adherence were independently and jointly associated with hypertension risk. These results support a potential oral-dietary axis in cardiovascular risk and underscore the need for integrated microbiome-dietary approaches to hypertension prevention.