Race/ethnic differences in respiratory problems among a nationally-representative cohort of young children in the United States

Using data from a nationally-representative cohort of young children in the United States, we ask the following: (1) Are there race/ethnic and birth weight differentials in the likelihood of developing respiratory problems by age three in a nationally representative birth cohort? (2) To what extent. does birth weight, vis-a-vis other key sociodemographic risk factors, mediate race/ethnic differentials in reported respiratory problems? (3) Does the effect of birth weight on respiratory problems risk differ by race? We find that non-Hispanic black children are 1.7 times as likely as non-Hispanic white children to be reported to have respiratory problems by age three, while the risk for Hispanic children is similar to that of non-Hispanic white children. Birth weight is also very strongly related to respiratory problem risk. Specifically, children born at very low weights (500-1499 a) have four times the odds of having respiratory problems of heavier children. Statistical controls for birth weight decrease the black-white differential by about 20%, while additional controls for sociodemographic factors reduce the race differential by an additional 35%. Finally, the net effect of birth weight is different for black and white children: whereas birth weight affects the risk of respiratory problems for black children only at low weights (< 1500 g), it remains an important predictor of excess risk for white children up to 3500 g.