Injury related infant death: the impact of race and birth weight.

OBJECTIVE: To examine the effect of race and birth weight independent of other sociodemographic factors on injury related infant death using national data.

SETTING: Infants born in the United States to mothers who were white (non-Hispanic), African American, Mexican American, and Native American.

METHODS: Linked infant birth and death data from the National Center for Health Statistics for 1989-91 were analyzed to calculate unadjusted and adjusted odds ratios for death due to homicide or unintentional injury within the first year of life. In addition to maternal race and birth weight, the risk of death was adjusted for maternal age, prenatal care, maternal education, paternal education, marital status, birth order, interval since last pregnancy, smoking during pregnancy, and alcohol intake during pregnancy.

RESULTS: Among 10.7 million births during 1989-91, 821 homicides and 2397 unintentional deaths were reported in infants. Relative to whites, African Americans were at highest risk for homicides (unadjusted and adjusted odds ratios = 3.6 (95% confidence interval = 3.1 to 4.2) and 1.6 (1.3 to 1.9), respectively) and Native Americans at highest risk for unintentional injuries (unadjusted and adjusted odds ratios = 3.8 (3.0 to 4.8) and 2.1 (1.7 to 2.6), respectively). After accounting for other sociodemographic factors, Mexican American infants appeared protected from injury (adjusted odds ratio = 0.7 (0.6 to 1.0) for homicides and 0.7 (0.6 to 0.8) for unintentional injuries). An inverse effect of birth weight was seen-as birth weight decreased, risk of homicides and unintentional injuries increased. After adjustment for the sociodemographic factors, very low birthweight babies were still at substantially increased risk of homicides with an odds ratio of 2.1 (1.4 to 3.1) and unintentional injuries with an odds ratio of 2.9 (2.4 to 3.7).

CONCLUSIONS: Using a large national data-set, the effect of race as a risk factor for fatal infant injuries was mostly explained by birth weight and other sociodemographic factors. Preventable risk factors need to be identified for African Americans and Native Americans, in particular. Birth weight is an important independent risk factor; very low birthweight babies should be monitored for both homicide and unintentional injury.