Racial discrimination and leukocyte glucocorticoid sensitivity: Implications for birth timing.

Abstract Rationale Psychological stress-induced cortisol elevations appear to contribute to preterm birth. Yet, some studies suggest that the biological ramifications of racial discrimination-associated stress are unique and may involve development of decreased glucocorticoid sensitivity despite normalized cortisol levels. Objective In this study, we examined the effects of racial discrimination on maternal cortisol output, leukocyte glucocorticoid sensitivity, and the degree of correspondence between cortisol levels and birth timing in an African American cohort. Method A generally healthy prospective cohort was enrolled at 28–32 weeks gestation (n = 91). The Experiences of Discrimination scale was administered, whole blood collected, and plasma cortisol levels, cytokine levels, and leukocyte counts quantified for examination of patterns of endogenous feedback. Results Racial discrimination in the mid-tertile was associated with greater maternal cortisol levels than the bottom tertile among women reporting internalizing responses (b* = 0.68, p = 0.001). Decreased leukocyte glucocorticoid sensitivity was witnessed at greater frequencies of experiences of racial discrimination, as evidenced by decreased correspondence between maternal cortisol levels and plasma IL-8 levels, monocyte counts, and lymphocyte counts (p values ≤ 0.043). The association between maternal cortisol levels and birth timing differed by discrimination tertile (p values ≤ 0.005), with greater cortisol levels predictive of earlier birth among women without (b* = −0.59, p < 0.001) but not with racial discrimination (p s ≥ 0.497). Conclusion We provide novel evidence of decreased glucocorticoid sensitivity at increasing frequency of exposure to racial discrimination. Our findings suggest that the biology of preterm birth may depend upon racial discriminatory exposures, favoring pathways dependent upon glucocorticoid-induced increases in leukocyte tissue surveillance versus glucocorticoid resistance-associated inflammatory aberrations at increasing levels of exposure. Precision approaches to prenatal care are sorely needed to combat preterm birth, particularly among African American women, with efforts dependent upon further research examining the pathways contributing to the syndrome dependent upon the totality of an individual's exposures. Highlights • Racial discrimination predicts lower maternal leukocyte glucocorticoid sensitivity. • Elevated cortisol levels predict earlier birth in women without past discrimination. • Findings suggest biology of preterm birth may be unique based on prior exposures. [ABSTRACT FROM AUTHOR]