Racial and ethnic infant mortality gaps and the role of socio-economic status

We assess the extent to which differences in socio-economic status are associated with racial and ethnic gaps in a fundamental measure of population health: the rate at which infants die. Using micro-level Vital Statistics data from 2000 to 2004, we examine mortality gaps of infants born to white, black, Mexican, Puerto Rican, Asian, and Native American mothers. We find that between-group mortality gaps are strongly and consistently (except for Mexican infants) associated with maternal marital status, education, and age, and that these same characteristics are powerful predictors of income and poverty for new mothers in U.S. Census data. Despite these similarities, we document a fundamental difference in the mortality gap for the three high mortality groups: whereas the black-white and Puerto Rican-white mortality gaps mainly occur at low birth weights, the Native American-white gap occurs almost exclusively at higher birth weights. We further examine the one group whose IMR is anomalous compared to the other groups: infants of Mexican mothers die at relatively low rates given their socio-economic disadvantage. We find that this anomaly is driven by lower infant mortality among foreign-born mothers, a pattern found within many racial/ethnic groups. Overall, we conclude that the infant mortality gaps for our six racial/ethnic groups exhibit many commonalities, and these commonalities suggest a prominent role for socio-economic differences.