Socioeconomic Determinants of Systolic Blood Pressure; Minorities' Diminished Returns.

BACKGROUND: Although socioeconomic position (SEP) is associated with better health, the protective effects of high SEP may be smaller for racial and ethnic minorities than Whites, as explained by Minorities' Diminished Returns theory. It is still unknown whether the association between SEP and systolic blood pressure (SBP) differs for racial and ethnic groups. The current study racial and ethnic variation in the association between SEP (education attainment and household income) and SBP among American adults.
METHODS: The National Health and Nutrition Examination Survey (NHANES; 2005-2006) included 4773 adults 20 years or older. Education attainment and household income were the predictor variables, SBP was the outcome variable, age and gender were the covariates, and race/ethnicity was the effect modifier. Multiple linear regression models were used in the pooled sample and each race/ethnicity.
RESULTS: In the pooled sample, higher education attainment and household income were associated with lower SBP, net of race, ethnicity, age, and gender. Race/ethnic stratified linear regression models showed protective effects of education attainment and household income against high SBP for Non-Hispanic Whites, a protective effect of household income for Other Hispanics, and no protective effects of education attainment or household income for other race/ethnic groups.
CONCLUSIONS: The health gain that follows SEP (education attainment and household income) are simply larger for the socially and economically privileged group (non-Hispanic Whites) and minimized for racial and ethnic groups. Given that the Minorities' Diminished Returns exist, policies and solutions that merely focus on reducing the racial gap in SEP may not eliminate the pervasive racial and ethnic gap in health problems including high SBP.