Chronic PM2.5 exposure and increased risk of hospitalization for kidney disease in São Paulo, Brazil

Exposure to fine particulate matter (PM_2.5) has been associated with an increased risk of chronic kidney disease (CKD), and exposure to PM_2.5 is known to aggravate ischemia/reperfusion injury-induced acute kidney injury (AKI) in mice. The impact of PM_2.5 concentration on the incidence of CKD, AKI, and glomerulopathy in the megacity of Sao Paulo is has never been described. We analyzed meteorological variables, PM_2.5 concentrations, and hospital admissions in São Paulo, Brazil, from 2011 to 2021. Admissions were categorized by age and sex. We analyzed 37,170 records, 55% representing males. Exposure to PM_2.5 was found to increase CKD hospitalization risk by 1-4 times (95% CI: 1.009-1.18), across different age groups and exposure levels. Long-term exposure to a high PM_2.5 concentration (65 μg/m³) increases that risk considerably for individuals aged 19-50 years (relative risk [RR]: 1.01; 95% CI: 1.005-1.015 and RR: 1.013; 95% CI: 1.01-1.018, respectively), the risk being ≤ 2.5 times higher in men aged 51-75 years (RR: 1.025; 95% CI: 1.015-1.032). The AKI hospitalization risk after prolonged exposure to high PM_2.5 concentrations was highest for men aged 19-50 years (RR: 1.04; 95% CI: 1.012-1.07). The risk of glomerulopathy was highest in the < 40-year age group, especially among men exposed to concentrations of 15 μg/m³ (RR: 1.02; 95% CI: 1.007-1.025) and 65 μg/m³ (RR: 1.07; 95% CI: 1.02-1.11). Such exposure also increased the cumulative risk of hospitalization for membranous nephropathy, regardless of sex and age. Our findings underscore the urgent need to develop global strategies for air pollution reduction.