But the researchers countered that they analyzed their data in several different ways. They also said the method Catalano suggested is not appropriate, according to their response to Catalano's editorial published on Feb. 7 in the same journal.
Catalano also said the premise of the study was problematic because the study does not look at how the president's party might be affecting infant mortality.
"You have to tell me what the connection is," Catalano told Live Science. "If they say it's changing healthcare, let's take a look and see." He added that this type of research is "about politics, its not about science."
The researchers stressed that studying the potential effects of social policies is within the realm of science, and does not imply a political bias.
"To the extent that human-made public, social and health policies and programs are powerful determinants of health, epidemiology is a social, and inherently political, science," they write in a counter-commentary. "It would be scientifically negligent to consider [the study of policy consequences] off-limits," they said.
Louise Flick, a professor of epidemiology at Saint Louis University in Missouri, who was not involved in the study, said that infant mortality is considered a very sensitive indicator of the general population's health "in that it is exquisitely responsive to poverty, maternal education, housing quality and other factors." However, "it is a surprise to me that there would be that much of a fluctuation in the relatively short period of a presidential term," Flick told Live Science.
Still, the link "fits with a lot of other research about the social determinants of health, and particularly about the impact of the income gap between the richest and the poorest members of a society," said Flick, whose own research focuses maternal and child health.
However, she noted that it may not be the president's party itself that affects infant mortality, but rather, something changing in society that leads to the election of a given president and contributes to a change in infant morality. "There could be forces changing in the country, either in attitudes of the population or economic circumstances, that lead to both a decline in [infant mortality] and the ease with which a democratic president could be elected," Flick said.
We should keep in mind that the U.S. has dropped steadily over the last 45 years in terms of its infant mortality ranking relative to other countries, Flick said. "So regardless of administration, we are not doing well," she said.
Live Science reached out to the study researchers, but they declined to comment for this article, saying they will issue a statement about the study next month.
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