Air pollution is associated with increased risks of acute rejection, graft loss, and death in kidney transplant recipients, a new national study finds.

Ambient air pollution containing fine particulate matter of 2.5 μm or less in aerodynamic diameter (PM2.5) has been previously linked with cardiovascular and respiratory diseases and diabetes, and more recently with chronic kidney disease and end-stage kidney disease.

In this study, investigators retrospectively examined air pollution exposure in the year before transplantation and the years following transplantation for 112,098 adult kidney transplant recipients from the 2004-2016 Organ Procurement and Transplantation Network. Compared with patients residing in areas with the lowest quartile of PM2.5 (1.2 to less than 8.3 μg/m3) prior to transplant surgery, patients residing in areas with quartiles 3 and 4 of exposure (9.8 to less than 11.9 μg/m3 and 11.9 to less than 22.4 μg/m3) had significant 11% and 13% increased odds of acute kidney rejection, respectively, in adjusted analyses, a team led by Tarek Alhamad, MD, MS, of Washington University School of Medicine in St. Louis, Missouri, reported in JAMA Network Open.

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Posttransplant air pollution exposure was significantly associated with a 17% increased risk for death-censored graft failure and a 21% increased risk for all-cause mortality per 10 μg/m3 increase in annual mean PM2.5 level.

The investigators estimated that the national burden of kidney graft failure associated with PM2.5 levels greater than the Environmental Protection Agency limit of 12 μg/m3 was 57 failures per year. They found the highest graft failure rates in densely populated areas with a high degree of air pollution, such as the Southwest and East North Central regions of the United States.

According to Dr Alhamad’s team, these findings suggest that “consistent exposure to fine particulate matter air pollution is associated with increased risk of worse transplant outcomes among recipients of [kidney transplants], including kidney rejection, kidney graft failure, and all-cause death.” They suggested that air pollutants, such as organic compounds, free radicals, and transition metals of PM2.5 or less may increase systemic inflammation and oxidative stress.

Kidney transplant recipients may want in move to areas with lower levels of PM2.5 for better graft function and longevity, according to the investigators.


Chang S-H, Merzkani M, Murad H, et al. Association of ambient fine particulate matter air pollution with kidney transplant outcomes. JAMA Netw Open. Published online October 7, 2021. doi:10.1001/jamanetworkopen.2021.28190