Allostatic load in the US general population: Race and educational intersection.

Objectives: Educational attainment is a protective factor against poor health, but high educational attainment has a weaker effect on black people than on white people; this pattern has been called marginalization-related diminished returns (MDRs). Using a national sample of white people and black people 25 years and above, this study estimates the association between high educational attainment and allostatic load between black people and white people, and within each group. Study design: This cross-sectional study uses data from the National Health and Nutrition Examination Survey (NHANES) between 1999 and 2016, including 2761 black people and 7058 white people. The outcome variable of interest was the Allostatic Load Scale (AL). We created the allostatic load scale by using 8 biomarkers, then created a binary variable (if ALS≥4 as 1 and ALS<4 as 0) to present elevated AL. Methods: We used several weighted modified Poisson regression models controlling for educational attainment (a predictor) and race (a moderator variable), age, sex, and marital status. We also controlled the models for smoking and drinking status as health behavior variables. As a sensitivity analysis, we ran several sets of regression analysis using the AL scale as a continuous outcome variable. Results: We found an inverse association between AL and educational attainment. The interaction between race and education has resulted in an inverse association between AL and educational attainment, with a weaker association in black people than in white people. We found similar findings by running regression models with AL as a continuous variable. Conclusions: We observed a weaker association between educational attainment and AL in black people than in white people, suggesting that educational attainment has more robust protection against allostatic load for white people than black people.