Preterm birth among African American and white women with a lifelong residence in high-income Chicago neighborhoods: an exploratory study.

OBJECTIVE To explore the association between race and preterm birth among women with a lifelong residence in high-income neighborhoods. METHODS Stratified and multivariable logistic regression analyses were performed on the Illinois transgenerational birthfile (infants born 1989-1991 and mothers born 1956-1975) with appended US Census income data. African American (n = 777) and non-Hispanic White (n = 2,327) infants born to mothers with a lifelong residence in Chicago census tracts with median family incomes in the top income quartile were studied. RESULTS African Americans had a twofold greater preterm (< 37 weeks) birth rate than Whites: 11.6% vs 5.2%, relative risk (95% confidence interval) equaled 2.2 (1.7-2.9). The adjusted (controlling for maternal birth weight, age, education, marital status, cigarette smoking, and prenatal care utilization) odds ratio of preterm birth for African Americans (compared to Whites) equaled 1.2 (.4-2.0). African Americans had a sixfold greater very low birth weight rate (< 1500 g) than Whites: 3.3% vs .6%: relative risk (95% confidence interval) equaled 5.9 (3.1-11.2). The adjusted odds ratio of very low birth weight for African Americans (compared to Whites) equaled 2.4 (1.1-3.9). CONCLUSIONS A stark racial disparity in the unadjusted rates of preterm birth and very low birth weight exists among women with a lifelong residence in high-income urban neighborhoods; however, the disparity narrows when traditional, individual-level risk factors are mathematically controlled.