Neighborhood Deprivation and Privilege: an Examination of Racialized-Economic Segregation and Preterm Birth, Florida 2019.

The Black-White disparity in preterm birth persists and is not fully explained by individual-level social, behavioral, or clinical risk factors. Consequently, there is increasing emphasis on understanding the role of structural and area-level factors. Racialized-economic segregation measured as the index of concentration at the extremes (ICE) simultaneously captures extremes of deprivation and privilege. Our objective was to examine associations between preterm birth (PTB) and the index of concentration at the extremes (ICE). In this cross-sectional study, we analyzed 193,957 Florida birth records from 2019 linked to 2015-2019 census tract data from the American Community Survey. We assessed PTB (< 37 weeks gestation) by subtypes: (1) early (< 34 weeks) and late (34-36 weeks) and (2) spontaneous and indicated (i.e., provider-initiated) deliveries. We calculated adjusted odds ratios (aOR) and 95% confidence intervals (CI) for three ICE measures: (1) ICE_INC: income, (2) INC_INC + WB: income + race/ethnicity (non-Hispanic White vs. Black), and (3) INC_INC + WH: income + race/ethnicity (non-Hispanic White vs. Hispanic). Results. For ICE_INC and INC_INC + WB, aORs for residing in the worst-off vs. best-off areas were 1.25 (95% CI: 1.12, 1.46) and 1.21 (95% CI: 1.07, 1.37) for early PTB, respectively, and 1.16 (95% CI: 1.05, 1.28) to 1.22 (95% CI: 1.12, 1.34) for indicated PTB. In conclusion, deprivation captured by ICE was associated with increased odds of early or indicated PTB. Eliminating PTB disparities may require a multifaceted approach that includes addressing the interplay between income and race/ethnicity in residential areas.