Associations between long-term exposure to ambient air pollution and renal function in Southwest China: The China Multi-Ethnic Cohort (CMEC) study

Background: Limited studies have examined associations between air pollutants exposure and renal function, especially in China, with the most extensive chronic kidney disease (CKD) disease burden worldwide. Objectives: This study examines associations between long-term exposure to ambient PM2.5, NO2, CO, O-3, SO2 and renal function. Methods: We included 80,225 participants aged 30-79 years from the baseline data of the China Multi-Ethnic Cohort (CMEC) study. Three-year average concentrations of PM2.5, NO2, CO, O-3, and SO2 were estimated using satellite-based spatiotemporal models. Renal function is determined by the estimated glomerular filtration rate (eGFR) using Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. After adjusting for covariates, generalized propensity scores (GPS) weighting regression was used to estimate associations between ambient air pollutants and renal function. Results: An increase of 0.1 mg/m(3) CO (OR [odds ratio] =1.20 95% CI [confidence interval], 1.05-1.37) was positively associated with CKD. An increase of 1 mu g/m(3) in SO2 (1.07, 1.00-1.14) concentration was positively associated with CKD. An increase of 10 mu g/m(3) in PM2.5 (1.17, 0.99-1.38), NO2 (1.12, 0.83-1.51) and O-3 (1.10, 0.81-1.50) concentration was not associated with CKD. These effects are stronger in those younger than 65, smoking and with low BMI. Conclusions: In this study, we found that long-term exposure to ambient CO and SO2 were positively associated with CKD. Gaseous pollutants should also arouse the concern of relevant departments.