Impact of ozone on kidney transplant outcomes.

Earlier work has shown adverse effects of air pollution on kidney disease outcomes, yet the specific impact of ozone (O3) on kidney transplant (KT) recipients remains unclear. We investigated the effects of long-term O3 exposure on KT outcomes by employing a multipollutant model. This multicenter, longitudinal cohort study included 4796 adult KT recipients who survived ≥1 year after transplantation from 2002-2020 at 3 major hospitals in South Korea. O3 and fine particulate matter (PM2.5) exposures were estimated using residential zip code-based high-resolution machine learning models. Associations between O3 exposure and all-cause mortality or death-censored graft failure were evaluated using time-varying Cox proportional hazards models adjusted for potential confounders, including PM2.5. The mean annual O3 and PM2.5 concentrations at 1 year posttransplant were 38.9 ± 11.3 μg/m3 and 26.7 ± 6.8 μg/m3, respectively. A 5-ppb increase in O3 concentration was associated with elevated risks of death-censored graft failure (hazard ratio, 1.60; 95% confidence interval, 1.40-1.82) and all-cause mortality (hazard ratio, 1.65; 95% confidence interval, 1.36-2.00). These associations remained consistent across subgroup and sensitivity analyses. The association of O3 with adverse outcomes in KT recipients extends understanding of the broad health consequences of air pollution.