Gender-specific protective effects of dietary index for gut microbiota on cardiovascular disease: insights from NHANES 2007–2020

BACKGROUND: Cardiovascular disease (CVD) represents a significant global health burden. The gut microbiome, as a potential regulatory factor, and its synergistic interaction with dietary patterns remains underexplored. The dietary index for gut microbiota (DI-GM), which quantifies the impact of diet on gut microbiota, has limited evidence of DI-GM's association with CVD, particularly regarding gender-specific effects and dose-response patterns. METHODS: This study utilized data from the National Health and Nutrition Examination Survey (NHANES) 2007-2020, which included 24,111 adult participants. We employed multivariable logistic regression models to assess the relationship between DI-GM and CVD. To explore possible nonlinear associations, we carried out a restricted cubic spline (RCS) analysis. Furthermore, we conducted subgroup analysis, gender stratification analysis, and sensitivity analysis. RESULTS: A 1-unit increase in DI-GM score was associated with a 4% reduction in CVD prevalence (adjusted OR = 0.96, 95% CI: 0.93-0.98, p = 0.002). Compared to the lowest quartile (Q1), the highest quartile (Q4) showed a 17% lower CVD prevalence (OR = 0.83, 95% CI: 0.72-0.95, p = 0.008). Subgroup analysis revealed a more pronounced association in women (OR = 0.95, 95% CI: 0.92-0.99, p = 0.026). Gender-stratified logistic regression and RCS confirmed a significant inverse linear relationship between DI-GM and CVD in women. Sensitivity analyses further validated the robustness of these findings. CONCLUSION: Dietary patterns with higher DI-GM scores were found to be linked to a lower prevalence of CVD, especially among women. These findings highlight DI-GM as a microbiota-targeted dietary strategy for CVD prevention. Prospective studies integrating multi-omics data are warranted to validate causality and elucidate sex-specific microbiota-mediated pathways.