Health Disparities
Allostatic load, racial and economic segregation, and birth outcomes Cynthia Wynn* Cynthia Wynn Beatrice Palazzolo Michael Petriello Gwendolyn S. Norman Nicholas Weil Ananda Sen Sarah S. Comstock Kimberly S. McKee
Objectives: Structural racism may affect birth outcomes through chronic stress. We examined if the Index of Concentration at the Extremes (ICE), a measure of racial and economic segregation, was associated with gestational age at birth and assessed allostatic load (i.e., the physiologic response to chronic stress) as a biosocial mechanism of structural racism.
Methods: Using data from the Michigan Archive for Research on Child Health cohort, part of the National Institutes of Health Environmental Influences on Child Health Outcomes Consortium, we examined a subset with select biomarkers and prenatal records. ICE scores ranged continuously from -1 to 1 (least to most privilege) and were categorized using quintiles. We operationalized allostatic load using eight parameters drawn from inflammatory biomarkers and prenatal records, deriving a sum score, then dichotomized as ≥4 (high) or <4 (low). We assessed, separately and together, the associations between ICE, allostatic load, and the outcome of gestational age at birth, using Generalized Estimating Equations with zip code as the cluster level.
Results: Of the n=389, 46% were Black, 16% of which were preterm compared to 9.6% of non-Black births. Black pregnant people were four times more likely to have an allostatic load score ≥4 (OR=4.1, 95% CI=2.2, 7.5) and had a significant half-week reduction in gestational age at birth (β=-0.6, 95% CI=-1.1, -0.06) compared to non-Blacks. Pregnant people living in the highest ICE quintile had shorter gestational ages at birth compared to the lowest quintile, but the effects were not significant (β=0.34, 95% CI=-0.37, 1.0). ICE was not associated with allostatic load ≥4 (p=0.6).
Conclusion: Although allostatic load was higher among Black pregnant people, we did not find evidence that ICE was associated with allostatic load or gestational age at birth. Other structural racism constructs may drive some of the racial differences in allostatic load and birth outcomes.