Abstract
BACKGROUND: The pathogenesis of metabolic syndrome (MetS) is strongly linked to dysbiosis in the gut microbiota. However, studies investigating the association between the dietary index of gut microbiota (DI-GM) and MetS are limited. As such, the present study aimed to examine the association between DI-GM and the prevalence of MetS, as well as long-term mortality among individuals in the United States. METHODS: Data from 30,372 participants, obtained from the 2007 to 2018 cycle of the National Health and Nutrition Examination Survey, were analyzed. Associations between DI-GM scores and the prevalence of MetS and long-term mortality were examined using weighted logistic regression and Cox regression, respectively. Restricted cubic spline (RCS) and subgroup analyses were performed to further explore these relationships. RESULTS: An inverse association was observed between DI-GM and the prevalence of MetS, with each 1-unit increase in DI-GM corresponding to an 8.2% decrease in MetS prevalence (odds ratio 0.918 [95% CI 0.896-0.941]). Among participants with MetS, a 1-unit increase in DI-GM was associated with reduced risk for cardiovascular mortality (hazard ratio 0.922 [95% CI 0.854-0.994]). RCS analysis revealed a significant linear inverse association between DI-GM scores and MetS prevalence and cardiovascular mortality among participants with MetS. Subgroup analyses suggested that race, income level, and smoking status may modify the association between DI-GM and MetS prevalence. CONCLUSIONS: Findings revealed that higher DI-GM scores were significantly associated with a lower prevalence of MetS in the general population and a reduced risk for cardiovascular mortality among individuals diagnosed with MetS. Further longitudinal studies are needed to confirm these associations and explore the underlying biological mechanisms.