Public goods and private resources as determinants of county low birth weight incidence

Abstract

Infants born at low birth weight are at elevated risk of infant mortality, developmental delays, and adulthood cardiovascular disease. That low birth weight (LBW; <2500 grams) incidence varies two-to-three-fold between racial/ethnic groups (e.g., black/African American relative to white) and across geographic areas (e.g., counties) is therefore a pressing public health concern. These differences in LBW incidence are at least partly due to the clustering of social and economic risks within historically marginalized racial groups and economically disadvantaged places, as well as dissimilar policy and community resource environments. In this dissertation, we seek to understand how differences in county incidence of LBW and county black-white disparities in LBW develop over time. Toward this end, we exploited within county changes in the provision of public services, and fluctuations in the private economic resources of residents, to understand their influence on LBW outcomes. Two studies presented herein use data from national birth records for fifteen years between 1992-2014, with data on birth weight and maternal characteristics aggregated to the county and pooled over three-year periods.

The first study examined whether changes in local government expenditures on two services (parks and recreation, and housing and community development) influenced county incidence of LBW and the black-white LBW gap. Local government expenditures were assessed every five years from 1992-2012 by the U.S. Census Bureau. Linear regression models were fit, adjusting for the lagged dependent variable, county and period fixed effects, local government expenditures in multiple categories, and county fluctuations in median income, percent of black residents, and population change. Results indicated that increases in parks and recreation expenditures were associated with reduced county LBW incidence (a $50 increase per capita reduced LBW incidence by 1.25 births per 100) but not black-white LBW disparities.

In the second study, the primary aim was to test whether county fluctuations in median income were associated with LBW outcomes, and the extent to which this link was explained by maternal sociodemographic and health risk factors. Median income and black-white differences in income were assessed in years that corresponded to the five measurement periods for LBW outcomes. Using county by period fixed effects models, increases in median income were associated with reduced county LBW incidence and a shrinking black-white gap in LBW. The link between median income and county LBW incidence was attenuated by 72% when adjusting for maternal sociodemographic characteristics. Models in both studies were also fit using the more clinically significant outcome of very low birth weight (<1500 g.), and results were generally in accord. These studies document area level policy and economic determinants that could be targeted in local initiatives to reduce the incidence of LBW and promote greater equity in outcomes between black and white infants—namely, by increasing parks and recreation services and supporting economic development initiatives or policies that improve income levels.