The Role of Neighborhood Greenspace in reducing Risk of Hypertensive Disorders of Pregnancy, Chronic Hypertension, and Racial Disparities in Maternal Morbidity

University Of Pennsylvania, Philadelphia PA

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Abstract

PROJECT SUMMARY Hypertensive disorders of pregnancy (HDP) are a leading cause of maternal mortality and morbidity in the US, particularly for Black patients who are at greatest risk of poor outcomes. In addition to contributions to maternal mortality, HDP increase the risk of chronic hypertension (cHTN), which can lead to cardiovascular (CV) disease. Our parent grant (R01HL157160) is focused on neighborhood greenspace and its impact on HDP and subsequent cHTN using observational and experimental methods. The objective of this supplement proposal is to add crucial variables relevant to climate change and health (CCH) to this project. We will bring Dr. Allan Just onto our team to add temperature and air pollution, specifically particulate matter <2.5µm in diameter (PM2.5) to GeoBirth which is the cohort on which our parent project is based. GeoBirth includes 116,000 pregnant patients who gave birth in two Philadelphia hospitals from 2008 to present. We will analyze the 89,827 Philadelphia residents who gave birth from 2008-2020. Our overarching hypothesis is that extreme heat and elevated PM2.5 exposure contribute to the risks of, and racial disparities in, HDP and cHTN after pregnancy. We propose the following aims: 1) Observational: Quantify associations of extreme heat with HDP and cHTN after pregnancy and determine the extent to which heat mediates racial disparities in these outcomes. We will analyze associations of extreme heat with risk of HDP using multilevel logistic regression adjusted for individual and neighborhood-level confounders (1a). We will determine if extreme heat exposure is associated with risk of cHTN within 5 years after pregnancy using survival analysis methods (1b). We will quantify the extent to which extreme heat exposure among Black patients contributes to Black-White HDP and cHTN disparities using causal mediation and interaction analyses (1c). 2) Observational: Quantify associations of PM2.5 with HDP and cHTN after pregnancy and determine the extent to which PM2.5 mediates racial disparities in these outcomes. We will perform analogous analyses to Aim 1, using trimester-specific PM2.5 exposure in lieu of temperature. 3) Experimental: Determine the extent to which vacant lot greening mitigates exposure to extreme heat. We will also use data from a completed cluster RCT (2011-2014) to examine the impact of greening on ambient temperature in neighborhoods with clusters of 541 vacant lots in three trial conditions: greened; trash clean-up only; and control. This study will advance the field of women's CVD research by addressing the impact of climate change-related exposures to HDP and cHTN that lead to disproportionately high rates of mortality among Black patients. Our findings will inform individual-level clinical prevention efforts of CVD through personal exposure reduction in addition to large-scale urban policy changes to mitigate heat and pollution exposures.