Gut microbiota partially mediates the effects of fine particulate matter on type 2 diabetes: Evidence from a population-based epidemiological study

Abstract Background Experimental studies have indicated that alterations in the gut microbiota might play a role in the pathway of diabetes induction resulting from particulate matter pollution with aerodynamic diameters  2.5 ). However, few human studies have examined such experimental findings. Here, we examine the mediating effects of gut microbial dysbiosis on the associations between PM 2.5 and particulate matter pollution with aerodynamic diameters  1 ) on diabetes using the Guangdong Gut Microbiome Project (GGMP) dataset. Methods A multistage cluster sampling method was employed to recruit adult participants from communities in Guangdong. Each participant was interviewed using a questionnaire, fasting blood and stool samples were collected, and the exposure to air pollutants was assessed using a spatiotemporal land-use regression model. The mediation analysis was conducted to estimate the associations among air pollutants, gut microbiota diversity and diabetes. Results Both PM 2.5 and PM 1 were positively associated with the risks of impaired fasting glucose (IFG) or type 2 diabetes and negatively associated with alpha diversity indices of the gut microbiota. The mediation analyses indicated that the associations of PM 2.5 and PM 1 with the risk of type 2 diabetes were partially mediated by the decrease in gut microbiota diversity. Moreover, we found that 79 (PM 2.5 on IFG), 84 (PM 2.5 on type 2 diabetes), 83 (PM 1 on IFG) and 89 (PM 1 on type 2 diabetes) bacterial taxa could partially mediate the associations of PM 2.5 and PM 1 with IFG and type 2 diabetes, respectively. The relative abundance of most Firmicutes , Proteobacteria and Verrucomicrobia bacteria were negatively associated with particulate matter (PM) concentrations and the risks of diabetes. Conclusions Long-term exposure to PM may increase the risk of diabetes, and alterations in the gut microbiota partially explained these associations.