UC San Diego

This study examined whether individual and neighborhood socioeconomic status (SES) relate to vascular reactivity to phenylephrine (PE) in 105 African-Americans and 106 Caucasian-Americans. Aim 1 examined whether SES mediates the relationship between ethnicity and pressor responsiveness to PE. Aim 2 examined how neighborhood SES and individual SES relate to pressor responsiveness to PE using multilevel modeling. Aim 3 tested the hypothesis that SES moderates the relationship between perceived discrimination and pressor responsiveness to PE in African -Americans. Neighborhood SES (% below the poverty line, per capita income) was assessed using census block data gathered from the Census Bureau. Individual SES (education and occupation) was measured using the Hollingshead Index of Social Position. The Scale of Ethnic Experience was used to assess perceived discrimination. Pressor responsiveness was calculated as the systolic and diastolic blood pressure (BP) response to a 100-microgram phenylephrine (PE) bolus administered to participants intravenously. The results revealed that education and occupation each partially mediated ethnic differences in diastolic pressor responsiveness to PE (Aim 1). Low education and occupation were each associated with larger BP increases when given PE. Multilevel analyses revealed that higher education was associated with smaller BP responses to PE only when percentage of neighborhood poverty was 5% or less. As neighborhood poverty increased, the beneficial effect of education on pressor responses was no longer significant. Contrary to what was expected, there was no interaction between SES and perceived discrimination on pressor responses in African-Americans. These results suggest that SES plays an important role in explaining ethnic differences in vascular reactivity to PE