Residential Racial Segregation, Socioeconomic Status, and Hypertension Risk in Black and White Americans: The REGARDS Prospective Cohort Study

Abstract

Background: Black adults experience the highest hypertension burden of any racial group. It is unclear whether different dimensions of residential segregation have different relationships with hypertension risk for Black and White people, or whether socioeconomic status explains any of the relationships.

Methods: We studied 6787 Black and White participants from the REGARDS (Reasons for Geographic And Racial Differences in Stroke) study, without prevalent hypertension and with follow-up for hypertension 9.4 years later. County-level segregation was defined using dissimilarity, isolation, and interaction indices. Associations between residential segregation indices and incident hypertension were estimated. Racial differences in associations and mediating effects of socioeconomic factors were assessed.

Results: Risk ratios (RRs) of incident hypertension were 1.06 per SD higher isolation index (95% CI, 1.03-1.09) and 0.96 per SD higher interaction index (95% CI, 0.93-0.99). The dissimilarity index was not associated with hypertension risk. Neighborhood socioeconomic status explained 19% of the association between the isolation index and hypertension incidence. Although there were no statistically significant racial differences in associations, the isolation index was marginally associated with higher risk of hypertension in Black people only (RR, 1.05 [95% CI, 0.98-1.12]), and neighborhood socioeconomic status was a marginally significant mediator of that association (RR indirect effects, 0.993 [95% CI, 0.98-1.0004]).

Conclusions: Findings indicated that living in racially segregated counties was associated with higher risk of hypertension, particularly for Black people. Higher neighborhood socioeconomic status may mitigate the negative effects of that aspect of residential segregation on hypertension development.

Keywords: health disparities; health inequities; hypertension; residential segregation; socioeconomic factors.