Gut microbiota partially mediates the effects of fine particulate matter on type 2 diabetes: Evidence from a...

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 μm (PM_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 μm (PM₁) on diabetes using the Guangdong Gut Microbiome Project (GGMP) dataset.

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.

Both PM_2.5 and PM₁ 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 PM₁ 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 (PM₁ on IFG) and 89 (PM₁ on type 2 diabetes) bacterial taxa could partially mediate the associations of PM_2.5 and PM₁ 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.

Long-term exposure to PM may increase the risk of diabetes, and alterations in the gut microbiota partially explained these associations.