Particulate Matter and Incident Chronic Kidney Disease in Japan: The Ibaraki Prefectural Health Study (IPHS).

ABSTRACT

Introduction: Global health hazards caused by air pollution, such as chronic kidney disease (CKD), have been gaining attention; however, air pollution-associated CKD has not been explored in Japan. Methods: We examined 77,770 men and women with estimated glomerular filtration rate (eGFR) ≥60 ml/min/1.73 m2 in the Ibaraki Prefecture who participated in annual community-based health checkups from 1993 at 40-75 years old and were followed up through December 2020. The outcome was newly developed kidney dysfunction with eGFR of <60 ml/min/1.73 m2 during follow-up. To assess air pollution, a PM2.5 exposure model was employed to estimate yearly means at 1 × 1-km resolution, converted into means at the municipal level. Hazard modeling was employed to examine PM2.5 concentrations in residential areas as a risk factor for outcomes. Results: Participants were distributed across 23 municipalities in the Ibaraki Prefecture, with PM2.5 concentrations between 16.2 and 33.4 µg/m3 (mean, 22.7 µg/m3) in 1987-1995 as the exposure period. There were 942 newly developed kidney dysfunctions during follow-up. Based on 1987-1995 PM2.5 concentrations as the baseline exposure, the multivariate-adjusted hazard ratio per 10-µg/m3 increase in PM2.5 for newly developed kidney dysfunction was 1.02 (95%CI, 0.80-1.24) in men and 1.19 (95%CI, 0.95-1.44) in women. Conclusions: Elevated PM2.5 did not represent a significant risk factor for incident CKD in a prefecture in Japan.