Ambient Air Pollution and Posttransplant Outcomes Among Kidney Transplant Recipients

Yijing Feng; Miranda R. Jones; JiYoon B. Ahn; Jacqueline M. Garonzik-Wang; Dorry L. Segev; Mara McAdams-DeMarco

Disclosures

American Journal of Transplantation. 2021;21(10):3333-3345. 

In This Article

Abstract and Introduction

Abstract

Fine particulate matter (PM2.5), a common form of air pollution which can induce systemic inflammatory response, is a risk factor for adverse health outcomes. Kidney transplant (KT) recipients are likely vulnerable to PM2.5 due to comorbidity and chronic immunosuppression. We sought to quantify the association between PM2.5 and post-KT outcomes. For adult KT recipients (1/1/2010–12/31/2016) in the Scientific Registry of Transplant Recipients, we estimated annual zip-code level PM2.5 concentrations at the time of KT using NASA's SEDAC Global PM2.5 Grids. We determined the associations between PM2.5 and delayed graft function (DGF) and 1-year acute rejection using logistic regression and death-censored graft failure (DCGF) and mortality using Cox proportional hazard models. All models were adjusted for sociodemographics, recipient, transplant, and ZIP code level confounders. Among 87 233 KT recipients, PM2.5 was associated with increased odds of DGF (OR = 1.59; 95% CI: 1.48–1.71) and 1-year acute rejection (OR = 1.31; 95% CI: 1.17–1.46) and increased risk of all-cause mortality (HR = 1.15; 95% CI: 1.07–1.23) but not DCGF (HR = 1.05; 95% CI: 0.97–1.51). In conclusion, PM2.5 was associated with higher odds of DGF and 1-year acute rejection and elevated risk of mortality among KT recipients. Our study highlights the importance of considering environmental exposure as risk factors for post-KT outcomes.

Introduction

Air pollution is a well-recognized risk factor for adverse health outcomes.[1–3] Worldwide, exposure to fine particulate matter (particulate matter with diameter <2.5 μM [PM2.5]) caused an estimated 4.2 million deaths and 103.1 million disability-adjusted life-years in 2015.[2] While previous studies have shown that air pollution increases the risk of cardiovascular disease, cancer, infection, and mortality,[4–11] there is emerging evidence that air pollution also affects kidney health. Elevated levels of PM2.5 are associated with incident kidney disease, decline of kidney function, and progression to kidney failure.[12–16]

It Is likely that even after a kidney transplant (KT), patients have higher vulnerability to the adverse effects of air pollution than the general population. KT recipients experience a high burden of cardiovascular disease and diabetes[17,18] which are associated with elevated susceptibility to the adverse effect of air pollution.[1,19–21] KT recipients are on chronic immunosuppression resulting in alterations in their immune system,[22,23] which increases their risk of air pollution induced infections and malignancy. Furthermore, PM2.5 could increase oxidative stress in the recipients, which is a risk factor for the development of delayed graft function (DGF).[24,25] Finally, air pollution may influence allograft function because long-term exposure to PM2.5 induces systemic inflammatory response, which may lead to DGF and solid organ rejection.[26–31]

Air pollution exposure is a modifiable risk factor that could be reduced or eliminated by policy regulations or personal-level strategies. However, there is sparse knowledge about the effects of air pollution among solid organ transplant recipients,[32–34] especially KT recipients. We sought to investigate the association between PM2.5 and adverse post-KT outcomes among adult recipients in the United States (US).

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