Association of air pollution with incidence of end stage renal disease in two European cohorts and effect modification by chronic conditions

Abstract

Background and aim: End-stage kidney disease (ESKD) poses a high burden on patients and the health system. While studies indicating associations of air pollution with chronic kidney disease are accumulating, studies on ESKD are still scant. We investigate the association of long-term exposure to nitrogen dioxide (NO2), fine particulate matter (PM2.5) and black carbon (BC) with ESKD in two large population-based European cohorts. Methods: Individuals in the Rome Longitudinal Study (RoLS) and the Vorarlberg Health Monitoring and Prevention Program (VHM&PP) were followed up with Dialysis and Transplant Registries from 1985 to 2019 and 2011 to 2019, respectively. Long-term exposures to NO2, PM2.5 and BC were approximated by concentration at residence determined with Europe-wide hybrid land use regression models at 100x100m scale. Hazard ratios (HR) were determined from Cox-proportional hazard models with age as time axis and adjusted for individual and neighbourhood confounders; effect modification by various factors was tested. Results: RoLS contributed 3,231 cases from 1,939,461 individuals (mean age 52.4 years; crude incidence rate (CIR) 0.22 per 1,000 person years ) and VHM&PP 501 cases from 136,823 individuals (mean age 42.1 years; CIR 0.14). In RoLS, ESKD was significantly associated with PM2.5 In RoLS (HR 1.37 [1.06, 1.76] for an increase of 5 µg/m³) whereas in VHM&PP, ESKD was associated with BC (HR 1.17 [0.98,1.39] for 0.5*10-5m-1), and NO2 (HR 1.14 [0.96,1.35] for 10 µg/m³). Statistically significant effect modification was found in RoLS for all pollutants with higher HRs in diabetic and hypertensive subjects. For example, comparing non-diabetics and diabetics, respectively, the HRs for PM2.5 was 1.24 (0.96,1.60) vs 1.86 (1.44,2.40) in RoLS. Conclusion: Air pollution was associated with ESKD in both cohorts and in Rome may possibly be a potent trigger for ESKD in persons with chronic conditions. Keywords: air pollution, end-stage kidney disease, long-term exposure, effect modification, cohorts