The mediating roles of gut microbiota in the associations of air pollution and meteorological factors with metabolic syndrome.

We characterized distinct gut microbial community clusters associated with metabolic syndrome (MetS) and identified key genera underlying these patterns. Health-associated clusters were dominated by beneficial genera such as Bacteroides and Prevotella with known metabolic protective functions. Environmental exposures (air pollution and temperature) were associated with gut microbiota composition, and may increase the risk of MetS. Our findings further suggest that specific bacterial genera, particularly Megamonas and Megasphaera, may statistically mediate the associations of long-term exposure to nitrogen dioxide (NO2), fine particulate matter (PM2.5), and ambient temperature with MetS risk. Integrating environmental exposure assessment with gut microbiota profiling offers a promising strategy for metabolic syndrome prevention and precision intervention.