Correlation, causation, and breastfeeding

An interesting piece in the Atlantic on breastfeeding. Here’s a snippet:

One day, while nursing my baby in my pediatrician’s office, I noticed a 2001 issue of the Journal of the American Medical Association open to an article about breast-feeding: “Conclusions: There are inconsistent associations among breastfeeding, its duration, and the risk of being overweight in young children.” Inconsistent? There I was, sitting half-naked in public for the tenth time that day, the hundredth time that month, the millionth time in my life—and the associations were inconsistent? The seed was planted. That night, I did what any sleep-deprived, slightly paranoid mother of a newborn would do. I called my doctor friend for her password to an online medical library, and then sat up and read dozens of studies examining breast-feeding’s association with allergies, obesity, leukemia, mother-infant bonding, intelligence, and all the Dr. Sears highlights.

After a couple of hours, the basic pattern became obvious: the medical literature looks nothing like the popular literature. It shows that breast-feeding is probably, maybe, a little better; but it is far from the stampede of evidence that Sears describes. More like tiny, unsure baby steps: two forward, two back, with much meandering and bumping into walls. A couple of studies will show fewer allergies, and then the next one will turn up no difference. Same with mother-infant bonding, IQ, leukemia, cholesterol, diabetes. Even where consensus is mounting, the meta studies—reviews of existing studies—consistently complain about biases, missing evidence, and other major flaws in study design. “The studies do not demonstrate a universal phenomenon, in which one method is superior to another in all instances,” concluded one of the first, and still one of the broadest, meta studies, in a 1984 issue of Pediatrics, “and they do not support making a mother feel that she is doing psychological harm to her child if she is unable or unwilling to breastfeed.” Twenty-five years later, the picture hasn’t changed all that much.

And here’s a snippet of econ-evidence, reaching a similar conclusion.

(Cross-posted from

One thought on “Correlation, causation, and breastfeeding”

  1. Why do the magazines say this?  Because it is much easier for American mothers to pass off their babies to another person to feed them and to get some sleep.  It plays on their need to say “no.”

    However, despite what some may try to pass of as minimal information on breastfeeding benefits, the overwhelming evidence is there that breastfeeding is best and even the formula companies will tell you that.

    In fact, the World Health Organization estimates that exclusive breastfeeding would SAVE the LIVES of thousands of children a year.

    What more could you ask for?


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