Study Explores Causes of Infant Mortality in the US South

In addition to higher rates of obesity and diabetes, the South region of the US has the highest rates of excess infant mortality in the county, and a new study explores reasons why this is this happening.

Writing in the American Journal of Preventative Medicine, researchers from the US Department of Health and Human Services' Maternal and Child Health Bureau analyzed data on infant births and deaths between 2007-2009, the most recent data set available.

The researchers' goal was to understand the principal conditions and factors that contribute to so-called excess infant mortality rates, or IMRs.

For all of the US, the rate of IMRs in the study period was 6.59 deaths per 1,000 live births. Looking at the data across the US regions, the researchers observed that there were 1.18 excess infant deaths per 1,000 live births in the South, a figure that represents about 1,600 excess infant deaths annually and more than 5,000 for the study period.

"Overall, prematurity, congenital anomalies, and sudden unexpected infant death [known as SUID] were the three leading causes of death in the South and the rest of the U.S. However, SUID and preterm-related death were the largest causes of excess infant mortality in the South compared to other regions," said lead investigator Ashley H. Hirai.

Race played a role in excess infant mortality, but it seemed to have a different impact in different states, the researchers found.

"For example, the majority of excess infant mortality was due to higher mortality rates among non-Hispanic white infants in Kentucky and Oklahoma," Hirai said. "Conversely, a majority of excess infant mortality in Florida, Georgia, Mississippi, South Carolina, and Louisiana could be explained by compositional differences due to a larger proportion of non-Hispanic black births, which reflects a persistent racial gap that exists across the country."

Pinpointing factors contributing to the IMR in the South will enable policy makers put more effective strategies at reducing the IMR into play.

"To reduce excess Southern infant mortality, comprehensive strategies addressing SUID and preterm birth for both non-Hispanic black and white births are needed, with state-level findings used to tailor state-specific efforts," Hirai said. "These findings can be used to inform the prioritization of strategies within the new infant mortality Collaborative Improvement and Innovation Network (CoIIN) that originated in the South and through other public and private efforts to improve birth outcomes and reduce infant mortality at local and national levels."