Objective: To determine whether racial differences in risk of low birth weight infants among black and white parents can be attributed to differences in demographic, behavioral, medical, and socioeconomic factors.
Methods: We analyzed 203,815 singleton births from the 1992 California birth certificate data set for the risk of very low birth weight (500-1499 g) and moderately low birth weight (1500-2499 g) infants. Additional study variables included maternal (race, age, education, marital status, parity, obstetric history, tobacco use, medical complications, medical insurance, and use of prenatal care), paternal (race, age, and education), infant (gestational age and gender), and community (median household income from the 1990 US Census) characteristics.
Results: For both very low and moderately low birth weight infants, the unadjusted risk associated with parental race showed a gradient of risk, from highest to lowest, for black mother/black father, black mother/white father, white mother/black father, and white mother/white father parents. After adjusting for other risk factors, the odds ratio associated with black mother/black father parents was reduced from 3.37 to 1.73 for very low birth weight infants and from 2.51 to 1.60 for moderately low birth weight infants, but both remained elevated. Interracial parents no longer had an elevated risk of very low birth weight infants and white mother/black father parents no longer had an elevated risk of moderately low birth weight, compared with white parents.
Conclusion: After controlling for parental, infant, and community factors, most but not all of the increased risk of low birth weight infants associated with black parental race was explained.