Association of PM2.5 Reduction with Improved Kidney Function: A Nationwide Quasiexperiment among Chinese Adults

Abstract

Background. Increasing evidence from human studies has revealed the adverse impact of ambient fine particles (PM2.5) on health outcomes related to metabolic disorders and distant organs. Whether exposure to ambient PM2.5 leads to kidney impairment remains unclear. The rapid air quality improvement driven by the clean air actions in China since 2013 provides an opportunity for a quasiexperiment to investigate the beneficial effect of PM2.5 reduction on kidney function. Methods. Based on two repeated nationwide surveys of the same population of 5115 adults in 2011 and 2015, we conducted a difference-indifference study. Variations in long-term exposure to ambient PM2.5 were associated with changes in kidney function biomarkers, including estimated glomerular filtration rate by serum creatinine (GFRscr) or cystatin C (GFRcys), blood urea nitrogen (BUN), and uric acid (UA). Results. For a 10 μg/m3 reduction in PM2.5, a significant improvement was observed for multiple kidney functional biomarkers, including GFRscr, BUN and UA, with a change of 0.42 (95% confidence interval [CI]: 0.06, 0.78) mL/min/1.73m2, -0.38 (-0.64, -0.12) mg/dL, and -0.06 (-0.12, -0.00) mg/dL, respectively. A lower socioeconomic status, indicated by rural residence or low educational level, enhanced the adverse effect of PM2.5 on kidney function. Conclusions. These results support a significant nephrotoxicity of PM2.5 based on multiple serum biomarkers and indicate a beneficial effect of improved air quality on kidney function.