Neighborhood racial composition and experiences of racial discrimination: Associations with cytokines during pregnancy among African American women

Background: Preterm birth rates are consistently higher in African American (AA) pregnancies compared to White pregnancies in the United States. Neighborhood racial composition, experiences of racial discrimination, and systemic inflammation are factors that have been associated with preterm birth and other adverse pregnancy outcomes that may account for these disparities. Here, we investigated whether perceived neighborhood racial composition and experiences of discrimination were predictive of cytokine levels during pregnancy among AA individuals. Methods: 545 AA individuals completed surveys and had blood samples collected at prenatal clinics in the Midwest at three timepoints (8–18,19-29, and 30–36 weeks gestation) throughout pregnancy. Pro-inflammatory [interferon (IFN)-γ, interleukin (IL)-6, IL-8, tumor necrosis factor (TNF)-α, macrophage migration inhibitory factor (MIF)] and anti-inflammatory cytokines (IL-10) were quantified. Multivariate and multilevel models were used to examine associations of perceived neighborhood racial composition and experiences of racial discrimination with cytokine levels, controlling for relevant covariates. Results: Perceived neighborhood racial composition was significantly associated with MIF at 30–36 weeks gestation in multivariate regression (p < 0.001). Living in neighborhoods with more compared to fewer White people was predictive of higher levels of MIF (b = 0.599, SE = 0.12, p < 0.001). Experiences of discrimination were also associated with higher levels of MIF (β = 0.141, SE = 0.07, p = 0.036). Neither predictor was associated with other cytokines. Follow-up analyses revealed that neighborhood racial composition was also predictive of higher MIF levels at 8–18 weeks gestation (p = 0.02) and at 19–29 weeks gestation (p = 0.04). Conclusions: Living in neighborhoods with more White individuals and having more lifetime experiences of racial discrimination were positively related to levels of the pro-inflammatory cytokine, MIF, among pregnant AA individuals. MIF's known positive relationships with chronic stress and preterm birth suggest that these elevations in MIF may have negative health consequences. Future studies should explore whether MIF serves as a pathway between neighborhood racial composition or experiences of racial discrimination and preterm birth risk among AA individuals.