Long-term exposure to ambient PM2.5 and its components associated with diabetes mellitus: Evidence from a large population-based cohort from China

Objective Association between PM2.5 components and diabetes mellitus (DM) remains unclear. We therefore aimed to investigate the associations of long-term exposure to PM2.5 components with DM.

Research Design and Methods This study included 69,210 adults with no history of diabetes from a large-scale epidemiologic survey in Southwest China from 2018-2019. The annual average concentrations of PM2.5 and its components were estimated using satellite remote sensing and chemical transport modeling. DM was identified as fasting plasma glucose ≥7.0 mmol/L (126 mg/dL) or hemoglobin A1c ≥48 mmol/mol (6.5%). The logistic regression model and weighted quantile sum method were used to estimate the associations of single and joint exposure to PM2.5 and its components with DM, respectively.

Results Per-standard deviation increases in the three-year average concentrations of PM2.5 (OR [odds ratio] =1.08, 95% CI [confidence interval], 1.01–1.15), black carbon (BC, 1.07, 1.01–1.15), ammonium (1.07, 1.00–1.14), nitrate (1.08, 1.01–1.16), organic matter (OM, 1.09, 1.02–1.16), and soil particles (SOIL, 1.09, 1.02–1.17) were positively associated with DM. The associations were stronger in those older than 65 years. Joint exposure to PM2.5 and its components was positively associated with DM (1.04, 1.01–1.07). The estimated weight of OM was the largest among PM2.5 and its components.

Conclusions Long-term exposure to BC, nitrate, ammonium, OM, and SOIL is positively associated with DM. Moreover, OM might be the most responsible for the relationship between PM2.5 and DM. This study adds to the evidence of a PM2.5–DM association and suggests controlling sources of OM to curb the burden of PM2.5-related DM.