Low Birth Weight: Race and Maternal Nativity— Impact of Community Income

Abstract

Background.  The purpose of this article is to determine the effect of community income as a co-factor in the association of low birth weight, race, and maternal nativity in New York City. Methods.  New York City birth records, 1988 through 1994, provided data on maternal and infant characteristics. There were 274 121 white and 279 826 black mothers included in this study. Black mothers were classified as US-born (South and Northeast) and foreign-born (the Caribbean, South America, and Africa). Based on the 1990 US census income data, census tracts of the city were aggregated by tertile of per capita income as low-, middle-, and high-income communities. Incidence of low birth weight was estimated by race, maternal nativity in the city as a whole, and each income community. Results.  Overall, black women had a substantially higher risk of low birth weight infants (<2500 g) than did whites (13.1% vs 4.8%). Foreign-born black mothers had a birth weight advantage over US-born black mothers (10.0% vs 16.7%). After controlling for socioeconomic and medical characteristics, the risks of low birth weight for blacks compared with whites were 0.95 (95% confidence interval: 0.87–1.03) and 0.86 (0.69–1.02) for Caribbean- and African-born black mothers, respectively. Moreover, in low-income communities, compared with white mothers, the risks for Caribbean- and African-born black mothers were 0.88 (0.79–0.97) and 0.77 (0.61–0.96), respectively. By contrast, US and South American-born black mothers had a consistently higher risk of low birth weight infants, regardless of community income level. Conclusion.  Low birth weight was significantly less frequent among whites than among blacks. However, this overall finding masked substantial variation among blacks, determined by maternal nativity and the income level of the community in which they lived. In fact, Caribbean- and African-born black mothers had birth outcomes generally similar to and, in poor communities, even more favorable than those for whites.