title: Impact of income and income inequality on infant health outcomes in the United States.
abstract: OBJECTIVE
  The goal was to investigate the relationships of income and income inequality with neonatal and infant health outcomes in the United States.
  
  
  METHODS
  The 2000-2004 state data were extracted from the Kids Count Data Center. Health indicators included proportion of preterm births (PTBs), proportion of infants with low birth weight (LBW), proportion of infants with very low birth weight (VLBW), and infant mortality rate (IMR). Income was evaluated on the basis of median family income and proportion of federal poverty levels; income inequality was measured by using the Gini coefficient. Pearson correlations evaluated associations between the proportion of children living in poverty and the health indicators. Linear regression evaluated predictive relationships between median household income, proportion of children living in poverty, and income inequality for the 4 health indicators.
  
  
  RESULTS
  Median family income was negatively correlated with all birth outcomes (PTB, r = -0.481; LBW, r = -0.295; VLBW, r = -0.133; IMR, r = -0.432), and the Gini coefficient was positively correlated (PTB, r = 0.339; LBW, r = 0.398; VLBW, r = 0.460; IMR, r = 0.114). The Gini coefficient explained a significant proportion of the variance in rate for each outcome in linear regression models with median family income. Among children living in poverty, the role of income decreased as the degree of poverty decreased, whereas the role of income inequality increased.
  
  
  CONCLUSIONS
  Both income and income inequality affect infant health outcomes in the United States. The health of the poorest infants was affected more by absolute wealth than relative wealth.
authors.affiliation: Department of Pediatrics, Children's Hospitals and Clinics of Minnesota, 347 Smith Ave N., Suite 302, Saint Paul, MN 55102-3355, USA. maren.olson@childrensmn.org
authors.forename: Maren E
authors.initials: ME
authors.lastname: Olson
authors.forename: Douglas
authors.initials: D
authors.lastname: Diekema
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Elliott
authors.forename: Colleen M
authors.initials: CM
authors.lastname: Renier
mesh_terms: D005190:Family; D005260:Female; D006304:Health Status; D006305:Health Status Indicators; D006801:Humans; D007182:Income / Q000706:statistics & numerical data*; D007226:Infant Mortality / Q000639:trends; D007229:Infant Welfare / Q000191:economics*; D007231:Infant, Newborn; D008297:Male; D012959:Socioeconomic Factors; D014481:United States / Q000453:epidemiology