Built environment as a mediator in the association between racial isolation

Research has shown that racial residential segregation of blacks in the US is associated with poor birth outcomes among blacks and whites; however, the mediating pathways through which segregation affects maternal and fetal health remain understudied. One of the main pathways through which segregation is hypothesized to act is the built environment, including neighborhood characteristics such as the quality of housing and access to healthy food stores. We tested whether the built environment played a mediating role in the relationship between neighborhood level racial isolation of blacks and birth outcomes among non-Hispanic blacks and non-Hispanic whites in Durham, North Carolina. Previously constructed indices of black isolation and characteristics of the built environment, including housing damage, property disorder, vacant housing, tenure, nuisances, and security, were linked to 2000 to 2008 birth data in the North Carolina Detailed Birth Record. Outcomes included birthweight, low birthweight, preterm birth, small for gestational age, and birthweight percentiles. In race stratified multilevel models that controlled for maternal level characteristics, property disorder and tenure were especially important full or partial mediators in the association between black isolation and continuous birthweight, low birthweight, and preterm birth among blacks. In contrast, among whites, housing damage, property damage, nuisances, tenure and vacancy acted as mediators in models for continuous birthweight and birthweight percentiles. Identifying mediating pathways will help guide public resources for reducing the racial disparity in birth outcomes between US blacks and whites.