Association of PM _2.5 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-in-difference 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.

All-cause mortality attributable to long-term changes in mean temperature and diurnal temperature variation in China: a nationwide quasi-experimental study

“…This method is beneficial for the inference of causality via adjustment for unmeasured and omitted confounding factors [7,8]. A DID or its variant design has been used in several studies to explore the health effects of long-term exposure to air pollution, with daily/yearly pollution concentrations across spatial units treated as measurements at different continuous time points [4,5,9]. However, research in which a causal model/design has been applied to analyze the long-term health effects of ambient temperature remains scarce.…”

Health benefits from the rapid reduction in ambient exposure to air pollutants after China's clean air actions: progress in efficacy and geographic equality

“…From 2013 to 2020, a 48% decrease in PM 2.5 concentration was associated with a 21% reduction in attributable deaths (1.75 [95% confidence interval 1.64–1.85] million in 2013 to 1.39 [95% confidence interval 1.27–1.51] million in 2020) [ 3 ]. CAAs were associated with improvements in multiple health indicators, including lung function [ 6 ], lung-cancer incidence [ 7 ] and survival rate [ 8 ], kidney function [ 9 ], blood lipids [ 10 ], physical functions [ 11 ], household medical expenditure [ 12 ], and mental health [ 13–15 ]. However, increases in O 3 concentrations, particularly during the first stage, increased mortality in populous eastern China [ 16 ].…”