Proportional differences in births and infant mortality rates among the triethnic population in Texas from 1984 through 1986
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1School of Public Health, University of Texas-Houston Health Science Center 77225.
Insights
African-American infants face higher mortality due to more preterm and low-birth-weight births, despite lower mortality rates for at-risk infants. Identifying causes of these ethnic disparities is crucial for reducing infant mortality.
Area of Science:
- Perinatal epidemiology
- Public health
- Neonatal mortality research
Background:
- Infant mortality is significantly higher among African-American infants compared to Anglo and Hispanic infants in Texas.
- Preterm gestation and low birth weight are primary predictors of infant mortality.
Purpose of the Study:
- To analyze the distribution of gestational ages and birth weights across ethnic groups (African-American, Anglo, Hispanic) in Texas.
- To compare neonatal, postneonatal, and infant mortality rates among these ethnic groups based on gestational age and birth weight.
Main Methods:
- Retrospective analysis of birth data and mortality rates in Texas.
- Stratification of births by ethnicity, gestational age, and birth weight.
- Comparison of mortality rates across ethnic and risk-factor strata.
Main Results:
- African-American infants were disproportionately born at earlier gestational ages and lower birth weights compared to Anglo infants.
- Hispanic infants showed a slight increase in preterm births but not low birth weight compared to Anglo infants.
- While preterm/low-birth-weight African-American infants had lower mortality rates than their Anglo counterparts, the higher proportion of at-risk births led to overall higher mortality.
Conclusions:
- Ethnic disparities in infant mortality are driven by both the proportion of births at risk (gestational age, birth weight) and the mortality rates within those risk categories.
- The higher incidence of preterm and low-birth-weight births among African-American infants contributes significantly to their elevated infant mortality rates.
- Further research into the biological and/or sociological factors underlying these ethnic differences in pregnancy outcomes and mortality risk is essential to reduce African-American infant mortality in Texas.
Abstract:
Birth at preterm gestation and/or with low birth weight is a major predictor of the infant mortality rate, which is twice as high in African-American as in Anglo and Hispanic infants in Texas. This study examined the relative proportions of Anglo, African-American, and Hispanic births that occurred in Texas at specific gestational ages and birth weights, and the neonatal, postneonatal, and infant mortality rates associated with those births. African-American infants showed a systematic tendency to be born at earlier gestational ages and with lower birth weights than did Anglo infants, while Hispanic-Anglo differences were limited to a small excess of preterm but not low weight Hispanic births. Preterm and low-birth-weight African-American infants had neonatal and infant mortality rates that were lower than those of Anglo infants, but that benefit was inadequate to compensate for the greater proportion of African-American births that were at risk. No consistent difference could be identified between Hispanic and Anglo infant mortality rates. We conclude that the birth weight and gestational age predictors of infant mortality reflect the combined effects of two ethnic-specific factors: the mortality rates at specific birth weights and gestational ages, and the proportions of births that are at risk. The biological and/or sociological causes for these ethnic differences in pregnancy outcomes and mortality risk need to be identified if the mortality rate of African-American infants in Texas is to be reduced.