Drivers of Black-White Disparities in Hypertension Risk After Pregnancy: Findings from CARDIA

Background

Hypertension is the leading risk factor for cardiovascular disease (CVD), with disparities observed by race. Few studies have examined how intersecting social and sex-based biological determinants influence hypertension incidence among parous individuals and across racial groups. The objective of this study was to examine whether female-specific CVD risk factors (e.g., adverse pregnancy outcomes), individual- (e.g., education), and structural-level (e.g., neighborhood) social drivers of health (SDoH), beyond traditional CVD risk factors (e.g., physical activity), explain the Black-White disparity in hypertension following pregnancy.

Methods

Parous individuals in CARDIA, a longitudinal cohort study beginning in 1985–1986, without hypertension prior to their first pregnancy were included. Race was self-reported at enrollment. Blood pressure was measured at each examination, with hypertension incidence was defined as the first elevated blood pressure (systolic ≥130 mm Hg or diastolic ≥80 mm Hg) or initiation of antihypertension mediation after baseline. Participant follow-up time began at the next exam following their first live delivery. Cox proportional hazards models with time-varying covariates calculated hazard ratios (HRs) and 95% confidence intervals (CIs). To quantify how much each set of covariates explained the Black–White difference in hypertension risk, the percentage reduction in the race coefficient was calculated following addition of female-specific CVD risk and SDoH in multivariable-adjusted regression models.

Results

Among 1653 participants (29.4±6.1 years), Black women (n=924) had higher hypertension incidence than White women (n=729): 41.4 vs. 18.5 per 1000 person-years; and an earlier median onset age (42 vs. 48 years). Following traditional risk factors, individual-level SDoH explained the largest disparity (7.52%), then female-specific factors (2.26%), and structural- level SDoH (1.50%). Black women remained at higher risk post-adjustment (HR 2.72, 95% CI 2.17 – 3.41).

Conclusions

Parous Black women face substantially higher hypertension rates than White women, persisting after accounting for traditional risks, female-specific risk factors, and SDoH.