Global and national burden of chronic kidney disease attributable to fine particles: An updated exposure-response...

Robust evidence is needed for the exposure-response function (ERF) linking chronic kidney disease (CKD) to long-term exposure to ambient fine particulate matter (PM_2.5). A three-stage mixed-effects meta-analysis framework was applied to estimate a nonlinear ERF that links PM_2.5 exposure to CKD risk ratio or estimated glomerular filtration rate (eGFR) reduction, by integrating all available evidence via systematic searches. Based on the derived ERF, we quantified the global and national burden of CKD attributable to PM_2.5 exposure above 10 μg/m³ from 1990 to 2020. A total of 38 studies on CKD and 16 on eGFR were included. Per 10 μg/m³ increment in PM_2.5, the pooled risk ratio of CKD was 1.32 (95% confidence interval [CI]: 1.21-1.43) and the ERF indicated a predominantly log-linear association; the pooled eGFR reduction was 2.115 mL/min/1.73 m² (95% CI: 0.452-3.777), and the ERF showed a saturated effect of high-concentration exposure. In 2020, PM_2.5 exposure was estimated to contribute to 485,000 (95% CI: 370,000-587,000) deaths, 5.77 million (95% CI: 4.51-6.99 million) incident cases, and 243 million (95% CI: 188-294 million) prevalent cases of CKD worldwide. Compared with level-2 risk factors for CKD mortality in the Global Burden of Disease study, PM_2.5 ranked first in 1990 and second in 2020, reaching a level of importance comparable to major metabolic risk factors. This study provides robust evidence that PM_2.5 is a substantial contributor to the global CKD burden and that clean air action is an urgent and integral CKD prevention.