Spatial social polarization and birth outcomes: preterm birth and infant mortality – New York City, 2010–14:

Aims: This study assessed the relationship between spatial social polarization measured by the index of the concentration of the extremes (ICE) and preterm birth (PTB) and infant mortality (IM) in New York City. A secondary aim was to examine the ICE measure in comparison to neighborhood poverty. Methods: The sample included singleton births to adult women in New York City, 2010–2014 (n=532,806). Three ICE measures were employed at the census tract level: ICE − Income (persons in households in the bottom vs top 20th percentile of US annual household income), ICE −Race/Ethnicity (black non-Hispanic vs white non-Hispanic populations), and ICE – Income + Race/Ethnicity combined. Preterm birth was defined as birth before 37 weeks’ gestation. Infant mortality was defined as a death before one year of age. A two-level generalized linear model with random intercept was utilized adjusting for individual-level covariates. Results: Preterm birth prevalence was 7.1% and infant mortality rate was 3.4 per 1000 live bi...