Long-Term Air Pollution and Blood Pressure in an African American Cohort: The Jackson Heart Study

African Americans are disproportionately affected by cardiovascular diseases, particularly hypertension. Although short-term exposure to air pollutants, such as fine particulate matter (PM2.5) and ozone (O3), may affect short-term blood pressure, much less is known about long-term effects on blood pressure. We examined associations between 1-year and 3-year mean PM2.5 and O3 concentrations with prevalent hypertension at study recruitment (visit 1, 2000-2004, N=5,193) and incident and prevalent hypertension after follow-up (visit 2, 2005-2008, N-4,105). We also examined systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure, and mean arterial pressure (MAP) among participants in the Jackson Heart Study, a large cohort of African Americans living in Jackson, Mississippi. We used log binomial regression to estimate prevalence ratios and risk ratios of hypertension associated with PM2.5 and O3 concentrations as well as linear regression models to estimate associations of PM2.5 and O3 concentrations with SBP, DBP, pulse pressure, and MAP. We adjusted for potential confounding by sociodemographic, behavioral, and clinical characteristics. We did not observe associations between an IQR (0.8 µg/m3at visits 1 and 2) increase in 1-year PM2.5 concentration and incident (RR 0.96, 95% CI 0.87, 1.06) or prevalent (PR 1.00, 95% CI 0.98, 1.01 at visit 1, PR 1.00, 95% CI 0.98, 1.02 at visit 2) hypertension or between an IQR (2.3 part per billion (ppb) at visit 1, 2.8 ppb at visit 2) increase in 1-year O3 concentration and incident (RR 0.92, 95% CI 0.82, 1.04) or prevalent (PR 1.00, 95% CI 0.99, 1.01 at visit 1; PR 1.00, 95% CI 0.97, 1.02 at visit 2). However, an IQR increase in 1-year O3 concentration was associated with 0.55 mmHg higher SBP (95% CI 0.12, 0.98), 0.41 mmHg higher DBP (0.17, 0.65), and 0.46 mmHg higher MAP (95% CI 0.19, 0.73) at visit 1. We observed similar associations with 3-year PM2.5 and O3 concentrations at visit 1. Our results do not provide evidence of an association with overall incident and prevalent hypertension, but provide some evidence indicative of small associations between air pollutants and DBP and MAP in an African American population with high prevalence (56% at visit 1) of hypertension.

Impact/Purpose

Hypertension is a major precursor to more severe cardiovascular disease, which is the leading cause of death in the US. African Americans have the highest prevalence of hypertension of any racial group. Short-term exposures to air pollution may influence short term blood pressure, but the long-term effects of air pollution on hypertension are less well understood, particularly among African Americans. We examined associations between long-term (1-year and 3-year) exposures to fine particulate matter (PM2.5) and ozone (O3) with incident and prevalent hypertension, as well as systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure, and mean arterial pressure (MAP) among a cohort of 5231 African Americans enrolled in the Jackson Heart Study. We observed associations between 1-year O3 exposure and SBP, DBP, and MAP at baseline but not after four years of follow-up. We observed similar associations with 3-year O3 and PM2.5 exposures. We did not observe associations between 1-year PM2.5 exposure and blood pressure indicators or between air pollutants and incident or prevalent hypertension. This study furthers our understanding of air pollution and hypertension in a population with a high prevalence of hypertension and is among the first to be conducted among African Americans.

Citation

Weaver, A., Y. Wang, G. Wellenius, A. Bidulescu, M. Sims, A. Vaidyanathan, D. Hickson, D. Shimbo, M. Abdalla, K. Diaz, AND S. Seals. Long-Term Air Pollution and Blood Pressure in an African American Cohort: The Jackson Heart Study. Elsevier B.V., Amsterdam, NETHERLANDS, 60(3):397-405, (2021). [DOI: 10.1016/j.amepre.2020.10.023]

DOI: Long-Term Air Pollution and Blood Pressure in an African American Cohort: The Jackson Heart Study