Improvements in infant death inequality between richest and poorest US counties have stalled since 2000: Study
Inequality in infant deaths between the richest and poorest US counties has narrowed by 76% since 1960 but that trend has stagnated since 2000, according to experts. The findings suggest both positive developments and concerning patterns. The reductions in death among poor populations coincide with the introduction of 1960s welfare programs and the study authors say these programs may have helped contribute to close to 20% of the reductions they identified, since the programs’ introduction.
“In terms of positive developments, we show that infant mortality rates have become more equal across the poorest and least poor counties in the US between 1960 and 2000, with our estimate of mortality inequality declining 76%. We estimate that this reduction in inequality accounts for nearly 20% of the overall national reduction between 1960 and 2000. In addition, we show that the gender gap in infant mortality rates narrowed substantially between 1970 and 2016,” says the research team in their analysis published in Science Advances.
“Yet, we also document that mortality inequality has remained roughly constant between 2000 and 2016 and that the level of inequality that remained in 2016 was roughly one-quarter of the 1960 level. The trend in recent years, together with the persisting level of inequality, suggests an important role for policies that improve the health of infants in poor areas,” the authors write.
Due to improvements in healthcare, infant mortality has been declining across all economic classes for decades, but it has been unclear how much of that decline is due to poverty reduction and how those changes have evolved over time. “In contrast to growing disparities in life expectancy between the rich and poor and increasing economic inequality, recent studies find decreasing inequality in mortality and health outcomes among younger age groups in the US. While there is a general understanding that poverty is associated with worse childhood health outcomes, including mortality, less is known about how such inequality evolved over a longer period,” says the research team. It includes experts from the Federal Reserve Board, Washington, DC, University of California, Berkeley, University of California, San Francisco and Massachusetts Institute of Technology, Cambridge.
To understand the relationship between infant mortality and poverty in the US and how has it changed over time, the team analyzed the association between infant mortality and poverty in the US between 1960 and 2016. They used county-level data on death rates from the US Centers for Disease Control and Prevention (CDC) and poverty data from the US Census Bureau, reaching back to 1960, the first year the Census included such a measure. For each decade since 1960, they combined counties into ventiles or twenty equally-sized groups of counties ranked by poverty rate.
They found improvements in both the poverty rate and the infant mortality rate across all counties and found that the difference in the infant death rate between the richest and poorest ventiles narrowed from 17.8 deaths per 1,000 births to 3.6. “Over the last 50 years, mean poverty and infant mortality rates fell considerably in the US. The average poverty rate decreased from 22.1% in 1960 to 14.7% in 2016, while mean infant mortality fell from 25.8 in 1960 to 5.8 in 2016.
The difference in average poverty rates between the poorest 5% of counties (top poverty ventile) and the least poor 5% (bottom poverty ventile) declined from 55.1 percentage points in 1960 to 22.0 percentage points in 2016,” says the team. They further say, “Level differences in infant mortality rates also narrowed between the most poor and least poor counties, declining from 17.8 in 1960 to 3.6 in 2016. The differences in both neonatal and postneonatal mortality rates between the most poor and least poor counties also narrowed meaningfully over this period.”
Nearly three-quarters of the decrease in death rates between the poorest and least poor counties occurred between 1960 and 1980, coincident with the introduction of antipoverty programs and improvements in medical care for infants. The authors estimate that 18% of the reduction in infant mortality since 1960 can be explained by declining inequality. However, infant mortality inequality did not significantly improve between 2000 and 2016, suggesting that further anti-poverty action is needed to eliminate this disparity, says the research team.