New York, Feb 18 (IANS): What do infants and toddlers have got to do with government of the day? A lot, claims research.

The study tries to establish that having a Democratic president in the US is linked with a reduction in infant mortality rates.

Researchers analysed US infant mortality rates from 1965 to 2010 - a period that saw four Democratic and five Republican presidents.

They found that infant mortality rates were about three percent higher during years in which a Republican was president, compared with the years in which a Democrat was president.

The findings held even after the researchers took into account factors that might affect infant mortality, such as unemployment rates, smoking rates, abortion rates and measures of national education and income level.

And the researchers did not consider the first year of any president's term, they said, because a president's policies would not be expected to affect mortality in the first year of his presidency.

The researchers said they were "struck by the consistency of the association we have uncovered".

If the findings are true, “the association could arise because of conditions existing for mothers and infants during Democratic vs. Republican administrations”, wrote the researchers from University of Michigan in the International Journal of Epidemiology.

The findings have already been challenged.

In an editorial published after the study in the same journal, Ralph Catalano, a professor of public health at the University of California, Berkeley, said the statistical methods the researchers used in the study were not appropriate for the type of data they were analysing.

But the researchers stood by their findings and stated that they had analysed their data in several different ways.