The Impact of Air Pollution on Kidney Function: A Two-Sample Mendelian Randomization Study

Background: Chronic kidney disease (CKD) represents a major global health challenge that leads to considerable morbidity and mortality. The influence of particulate matter (PM)2.5, PM2.5–10, PM10, nitrogen oxides (NOX), nitrogen dioxide (NO2) on renal diseases has raised concerns. However, the etiological relation remains uncertain. This study aimed to establish genetic support for causal links between environmental exposures and renal impairment. Methods: A two-sample Mendelian randomization (MR) study was launched based on genome-wide association study. The inverse variance weighted method served as the primary analysis, complemented by four other approaches (MR-Egger, MR-Weighted median, weighted mode, and simple mode). The results were reinforced by MR-Egger regression, MR-PRESSO, and leave-one-out analysis. Results: The MR analysis revealed that exposed to PM2.5–10 significantly increases the risk of developing CKD (OR: 1.631; 95% confidence interval [CI]: 1.161, 2.290), eGFRcrea (β: −0.013; 95% CI: −0.021, −0.004), and eGFRcys (β: −0.024; 95% CI: −0.039, −0.008). NOx exposure correlated with declining eGFRcys (β: −0.016; 95% CI: −0.029, −0.003). NO2 correlated with increased urine albumin-to-creatinine ratio levels (β: 0.039; 95% CI: 0.009, 0.069). However, no significant association was found between exposure to PM2.5 or PM10 and impaired renal function, with no evidence of significant heterogeneity or horizontal pleiotropy. Conclusion: By employing MR analysis, we found that elevated levels of air pollutants, specifically PM2.5–10, can causally worsen kidney function. These results facilitate a deeper comprehension of the pathogenesis and treatment of air pollution-induced renal damage.