Associations between PM2.5 exposure and hypertension differ by neighborhood among heart failure patients in the state of North Carolina.

Background Both exposure to PM2.5 air pollution and neighborhood socioeconomic status (SES) are associated with adverse cardiovascular outcomes, including hypertension. In this study, we used the EPA-CARES electronic health record database to study the joint impact of neighborhood SES and PM2.5 exposure on hypertension among patients with heart failure in North Carolina. Methods We used urbanicity, housing factors, and socioeconomic factors from the 2010 Census to create neighborhood clusters using Ward’s hierarchical clustering algorithm. We then matched neighborhood clusters and PM2.5 annual average concentrations to the primary residence of heart failure patients observed at a University of North Carolina Healthcare System affiliated hospital or clinic (N = 30,060). PM2.5 concentrations were modeled at a 1x1 km resolution using a hybrid satellite-based model. We examined the associations between PM2.5 and hypertension, by neighborhood cluster and overall, using logistic regression models adjusted for age, sex, race, chronic kidney disease, diabetes, peripheral artery disease, hyperlipidemia, and chronic obstructive pulmonary disease. Results Hierarchical clustering resulted in seven neighborhood clusters. PM2.5 concentrations ranged from 9.5 µg/m3 in lower-SES rural cluster to 10.4 µg/m3 in upper-middle-SES urban cluster. We observed associations between PM2.5 and hypertension among lower-SES urban (OR=1.05, 95% CI 1.00-1.10), lower-middle-SES urban (OR=1.03, 95% CI 1.00-1.07), and middle-SES urban (OR 1.04, 95% CI 0.98-1.10) clusters and overall (OR=1.02, 95% CI 1.00-1.04) We did not observe associations between PM2.5 and hypertension in rural, suburban, or upper-SES urban clusters. Conclusions Among heart failure patients, we observed associations between PM2.5 and hypertension in lower- and middle-SES urban areas. These results suggest that associations between PM2.5 and hypertension can vary by neighborhood among individuals with severe cardiovascular disease. The use of electronic health records may greatly advance our understanding of air pollutant health effects by neighborhood SES, particularly in vulnerable populations. This abstract does not reflect EPA policy.

Impact/Purpose

Hypertension, or high blood pressure, is common in the United States and is a major risk factor for more serious cardiovascular disease. Exposure to fine particulate matter air pollution (PM2.5) has been shown to be associated with hypertension. Other factors, like socioeconomic status (SES) at the individual and community level, are also associated with hypertension. We conducted this study to examine whether associations between PM2.5 and hypertension are different in neighborhoods with different SES. We examined associations between PM2.5 and hypertension among patients with heart failure in the state of North Carolina. Patients were assigned to one of seven neighborhood clusters, based on Census data of indicators of SES where they live. We then examined associations between PM2.5 and hypertension by neighborhood cluster and overall. We observed that PM2.5 is associated with hypertension in lower-SES urban areas, lower-middle-SES urban areas, middle-SES urban areas, and overall. We did not observe associations between PM2.5 and hypertension in rural, suburban, or upper-SES urban areas in this population of heart failure patients. This has implications for environmental justice and air pollution epidemiology.

Citation

Weaver, A., E. Pfaff, L. Neas, R. Devlin, J. Schwartz, Q. Di, W. Cascio, D. Diaz-Sanchez, AND C. Ward-Caviness. Associations between PM2.5 exposure and hypertension differ by neighborhood among heart failure patients in the state of North Carolina. International Society for Environmental Epidemiology, Washington, D.C, August 23 - 27, 2020.