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 (PM_2.5) 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 PM_2.5. The mean annual O₃ and PM_2.5 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.