Risk associations between perceived stress, allostatic load and insulin resistance among nondiabetic African American women in the Jackson Heart Study
Objectives. The purpose of this study was to evaluate the associations between perceived stress, allostatic load, and insulin resistance measured by HOMAIR among nondiabetic African American women of the Jackson Heart Study.
Methods. The investigative team examined the cross-sectional associations (2000-2004) of perceived stress, summary indices of allostatic load, and insulin resistance in 2,245 nondiabetic African American women, stratified by glycemic profile, participating in the Jackson Heart Study. Measurements include physiological markers, anthropometric measures, and (3) stress instruments: Weekly Stress Inventory (WSI), Global Stress (STS), and JHS Discrimination Questionnaire (DIS). t-tests, χ2 test, bivariate correlations, and forward hierarchical linear regression were used to analyze the data. Results: Increased allostatic load scores were associated with insulin resistance among both, euglycemic and prediabetic women of the JHS. Among the prediabetic group, the only consistent associations were allostatic load scores with no contribution from the set of covariates or perceived stress measures. In the euglycemic group, associations with insulin resistance persisted with the set of covariates in the model, specifically age and BMI, and after adjusting for perceived stress. Of the perceived stress instruments, Everyday Discrimination was the only measure associated with insulin resistance among the euglycemic group. Although there was some evidence among the euglycemic group that physical activity was inversely associated with insulin resistance, after adjusting for allostatic load scores, the association was not maintained.
Discussion. Findings support the hypothesis that the persistent day-to-day stress of discrimination can lead to an insulin resistant state and be detrimental to the health of African Americans by leading to cumulative "wear and tear" on multiple body systems. Other types of stress, such as general and acute stressors in this study, were not found to contribute to increased allostatic load scores or insulin resistance.
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