An examination of racial/ethnic and socioeconomic differentials in allostatic load biomarkers and the subsequent effects on mortality outcomes in the United States

This study expands on previous research regarding associations between chronic stress biomarkers, allostatic load, and how elevated levels of allostatic load translate into increased mortality risk. The study uses data from the National Health and Nutrition Examination Survey III (NHANES III) gathered between 1988 and 1994, and four waves of the continuous NHANES gathered between 2003 and 2010. The NHANES III data were linked to the National Death Index (NDI) to obtain up to 18 years of mortality follow-up, measured through December 2006. The key findings include, (1) that patterns of associations between individual biomarkers and the underlying allostatic load concept differ significantly by race/ethnicity and educational attainment; (2) that comparisons of three different methods of calculating allostatic load differ in terms of reliability statistics, where count-based methods have higher internal consistency than the z-score summation method; (3) that observed racial/ethnic differences in allostatic load can be attributed to differential returns on education, where racial/ethnic differences are observed only for individuals with higher levels of education; (4) that all-cause mortality risk for non-Hispanic Blacks is affected to a greater extent by allostatic load than non-Hispanic Whites and Mexican-Americans; and (5) that allostatic load has a greater impact on diabetes-related death than other specific causes.