Racial Difference in the Association of Long-Term Exposure to Fine Particulate Matter (PM2.5) and Cardiovascular Disease Mortality among Renal Transplant Recipients

Ambient air pollutants are known risk factors for cardiovascular disease (CVD) morbidity and mortality with significant racial disparities. However, few studies have explored racial differences among highly susceptible subpopulations, such as renal transplant recipients (RTRs). Despite improvements in quality of life after transplantation, CVD remains the major cause of mortality, especially among Black recipients. This study aimed to evaluate potential racial differences in the association between long-term levels of PM2.5 and the risk of all-cause, total CVD, and coronary heart disease (CHD) mortality among RTRs. This retrospective study consists of 93,857 non-smoking adults who received a renal transplant between 2001 and 2015. Time-dependent Cox regression was used to assess the association between annual concentrations of PM2.5 and mortality risk. In the multivariable-adjusted models, a 10 μg/m3 increase in ambient PM2.5 levels found increased risk of all-cause (HR = 3.45, 95% CI: 3.08-3.78), CVD (HR = 2.38, 95% CI: 1.94-2.92), and CHD mortality (HR = 3.10, 95% CI: 1.96-4.90). Black recipients had higher risks of all-cause (HR = 4.09, 95% CI: 3.43-4.88) and CHD mortality (HR = 6.73, 95% CI: 2.96-15.32). High levels of ambient PM2.5 were associated with all-cause, CVD, and CHD mortality. The association tended to be higher among Black recipients than non-Blacks.