PSA

Have you seen this story about a new study showing that bottle-fed children are more likely to have significant behavior issues? I have to put in an interlibrary loan request for the original paper, but I am throwing up a quick post tonight. It seems inevitable to me that this post will spark nasty exchanges of fire from the trenches of the mama wars, and I suspect the participants will mostly be missing the point.

I have written before about Michael Kramer's fantastic longitudinal study in Belarus, in which he took something like 16,000 women who planned to breastfeed and assigned them randomly to healthcare providers and hospitals. One set of HCPs had been through Baby Friendly training to equip them to offer more effective breastfeeding support; the other set of HCPs hadn't had any special training. Kramer found substantial differences in breastfeeding exclusivity and duration, and he's following the kids longitudinally to see how they're doing. This is the project that found breastfed kids scored half of a standard deviation higher on verbal IQ tests at age 6, a finding (.pdf link) that still blows my mind.

They also looked at the kids' behavior at age 6, based on reports from mothers and teachers. You can read the whole article for free if you're so inclined, but here's the money quote:

On the basis of the largest randomized trial ever conducted in the area of human lactation, we found no evidence of risks or benefits of prolonged and exclusive breastfeeding for child and maternal behavior.

So the moms who are, inevitably, going to be trading horror stories about badly behaved children in response to this new study ("You should see my nephew, Dharma Patchouli -- my SIL breastfed him until he was seven and he knows no limits. He climbed the chandelier at my wedding reception and she laughed about how great it was to watch him exploring" vs. "Well, my poor niece Adelina Lonelyheart felt so little love in those months she spent strapped in her baby bucket with a pacifier shoved in her mouth that now she cries at the drop of a hat.") -- moms who get sucked into exchanges like that are missing the mark here. Breastfeeding duration isn't associated with any differences in average kids' behavior scores. This is a popular idea with some breastfeeding families -- I have an edition of The Womanly Art of Breastfeeding in which a mother of several children says, "The longer we breastfed them, the better they turned out" -- but it's not supported by the PROBIT data.

This new study is talking about behavior that's not average-- kids who are at or above the 90th percentile for a particular type of problem behavior (caveat: this is based entirely on the newspaper report). This makes a lot of sense to me: if a kid is genetically predisposed toward anxiety, say, and then doesn't get the long-chain fatty acids that we know are important for building a healthy brain, he may have more trouble regulating his anxious feelings down the line. It's not about how it makes someone crazy when her nephews burp loudly at the table and CLEARLY it's their mother's fault. This study is about significant anxiety or oppositional behavior or other outside-the-normal-range concerns.

There does seem to be a bit of a contradiction between this study and the PROBIT study, but a partial explanation may be that the great strength of the PROBIT study (the shared intent to breastfeed, which made randomization possible) is also a weakness: every mother who participated was planning to breastfeed her child. All of the PROBIT findings are thus comparing two groups of breastfed children, and we know from the literature on breastfeeding and schizophrenia that even a few weeks of breastfeeding can be linked to differences in long-term psychiatric outcomes.

Now that I've dashed off this post, I'm a little hesitant about publishing it. (The scholar in me is saying, "Neeeeeed the full text! Muuuuuust have full text!") If you disagree with me, please be nice. If I find out more from the actual article, I'll be sure to post an update.