Infant Mortality in the United States: Trends, Differentials, and Projections, 1950 through 2010
This study examined long-term trends and differences in infant mortality in the US from 1950 to 1991 according to race and ethnicity, education, family income, and cause of death. Forecasts are made through the year 2010.
Log-linear regression models were applied to data from the National Vital Statistics System, National Linked Birth and Infant Death files, the National Maternal and Infant Health Survey, the National Natality Survey, and the National Infant Mortality Survey to model and forecast infant mortality. Although the infant mortality rate in the US has declined steadily since 1933, it is consistently higher than that for many other industrialized countries. The relatively unfavorable international standing of the US in terms of infant mortality rates stems in large part from the substantial racial disparity in infant survival and associated socioeconomic inequality that have existed in the country for a long period. Dramatic declines in the US infant mortality rate have occurred in the past 4 decades, largely as a result of declines in mortality from pneumonia and influenza, respiratory distress syndrome, prematurity and low birthweight, congenital anomalies, and accidents. Despite the overall reductions, however, substantial racial/ethnic, educational, and income differences in infant mortality still exist. In fact, black-white disparity in IMR increased from 1950 to 1991. Between 1951 and 1990, neonatal mortality declined much faster than postnatal mortality in the total population. White babies followed the trend of the whole population while black babies experienced a more rapid decline of postnatal mortality than of neonatal mortality. Like infant mortality, neonatal mortality has seen an increasing racial inequality over time; while postnatal mortality has seen a narrowing of black-white differentials, especially in the last 30 years. Amongst other racial/ethnic groups, Japanese, Chinese, Cuban, Central/South American, and Mexican infants had lower infant mortality than white infants while Puerto Rican, Hawaiian, and American Indians (and blacks, of course, who have the highest infant mortality of all), had higher infant mortality than whites. Infant mortality is inversely associated with maternal education and family income. However, the black-white infant mortality disparity was greater as higher levels of maternal education and the racial disparity generally increased across all educational levels during 1964 through 1987. Moreover, the racial disparity appeared to have increased between 1964 and 1988 for the middle income and highest income categories.
Congenital anomalies were the leading cause of infant death for the total population in 1991, accounting for 1 in 5 infant deaths, followed by SIDS, prematurity and low birthweight, and respiratory distress syndrome. For black babies, the leading cause was prematurity/low birthweight (which increase by about 9% from 1981 to 1991) followed by SIDS and congenital anomalies. The long-term downward trend in US infant mortality has not benefited Blacks and Whites equally. The Black-White disparity in infant mortality has not only persisted but increased over time and is not expected to diminish in the near future. Educational inequalities have also widened, and racial disparities have generally increased across all educational levels.