Combined toxicity of outdoor air pollution on kidney function among adult women in Mianyang City, southwest China.

Environmental pollution is a risk factor for kidney dysfunction. However, the combined toxicity of air pollutants on kidney function is scarce. We estimated the relationship between combined toxicity of air pollutants and kidney function among adult women (n = 7071, 18-65 years old) in Mianyang City, Southwest China. We measured serum concentrations of uric acid, urea, creatinine, and cystatin C, and we calculated the individual estimated glomerular filtration rate (eGFR) using a cystatin C-based equation developed specifically for Chinese patients with CKD equation. Air pollution data were collected to calculate the individual average daily dose (ADD) of pollutants based on the air quality complex index (AQCI). Mean AQCI was higher in winter and lower in summer, and followed the monthly and seasonal trends of air pollutants. Concomitantly, individual ADD was also higher in winter and lower in summer, and the seasonal differences were reflected in the levels of kidney biomarkers (including uric acid, urea, creatinine, cystatin C, and eGFR). With an interquartile range (IQR: 1.04-1.50 m/day/kg) increases of ADD, the serum concentrations of uric acid, urea, creatinine, and cystatin C increase [B (95%CI): 1.774 (0.318, 3.231) umol/L, 0.218 (0.1888, 0.247) mmol/L, 1.501 (1.016, 1.986) umol/L, and 0.006 (0.003, 0.009) mg/L, respectively], whereas eGFR decreases [B (95%CI): -0.776 (-1.106, -0.446) mL/min/1.73 m]. Totally, the relationship between combined toxicity of air pollutants and kidney function in Chinese adult women suggests that the toxicity of combined air pollutants inversely affects kidney function, which might accelerate the risk of CKD.