Changes in PM_2.5-related diabetes risk under the implementation of the clean air act in Shanghai

We examined the associations between PM_2.5 exposure and Type 2 diabetes mellitus risk under the implementation of the Clean Air Act (CAA) among high-risk population for diabetes in Shanghai.

A total of 10,499 subjects from the Shanghai High-Risk Diabetic Screen (SHiDS) project between 2002 and 2018, linked with remotely sensed PM_2.5 concentrations, were enrolled in this study. Ordinary least squares and logistic regression were applied to explore associations between PM_2.5 and diabetes risk in various exposure periods.

In year 2002-2013 (before CAA), the diabetes risk increased 7.5 % (95 % CI: 1.018-1.137), 8.0 % (95 % CI: 1.022-1.142) and 7.9 % (95 % CI: 1.021-1.141) under each 10 μg/m³ increase of long-term (1, 2 and 3 years) PM_2.5 exposure, respectively. Elevated PM_2.5 exposure were also associated with a significant increase in glycemic parameters before CAA implementation. However, in the year 2014-2018 (after CAA), the associations between PM_2.5 exposure and diabetes risk were not significant after controlling for potential confounders.

Our findings suggest that long-term and high-level exposure to PM_2.5 was associated with increased prevalence of diabetes. Moreover, the implementation of CAA might ameliorate PM_2.5-related diabetes risk.