Make mine milk?

University of Michigan researchers have found a higher rate of diarrhea among formula-fed babies than among babies on cow's or breat milk. But, they caution, their finding needs confirmation and explanation.

James S. Koopman, Verna Jean Turkish and Arnold S. Monto report in the May AMERICAN JOURNAL OF PUBLIC HEALTH on a comparison of 143 babies with gastrointestinal illness and 143 babies without. In analyzing the data they found that babies on formula were at six times the risk of babies on breast milk, and 2.5 times the risk of babies on cow's milk.

What the researchers did was a case-control study -- the infants were paired for sex, age, geography, health history, socio-economics, pets, family size and sibling school attendance. But case-control studies have their weaknesses, says Monto. "There are always other factors that one can't imagine -- in this case, that could have caused the selection of one type of milk over another -- and that factor may be responsible for the difference." Unless confirmed by further work, the study should not be the basis of public health recommendations on formula use, he says -- a sentiment echoed in an accompanying editorial.