Yesterday, a new study came out on the long-term effects of breastfeeding. The major limitation of this kind of research is that sociodemographic factors are so intertwined with breastfeeding behavior and long-term outcomes that it is nearly impossible to correct for this statistically. So Cynthia Colen did something smart: she looked at families in which one sibling was breastfed while the other wasn’t and in this way was able to circumvent all the unknown confounding factors. Her results have been highlighted on many news websites because they show that there are virtually no long-term benefits of breastfeeding. The most important findings are explained here by The Skeptical OB.
However, when I read the paper I couldn’t find one important piece of information: how long did these mothers breastfeed for? In this news article it says an average of six months, but those data (and the standard deviation) are nowhere to be found in the paper (or is it me and did someone else find them?!). The authors of the paper do report that there is no correlation between the long-term outcomes and the duration of breastfeeding, but since an average of six months is a lot less than the AAP recommended year, I still wonder if we can draw these conclusions from this study. Another piece of information that I missed is if in the discordant sibling sample, the first sibling was more likely to be breastfed than the second or the other way around. I want to know these things so I can judge this paper better!
An important factor that I’m missing in the current news reporting on this paper is that breastfeeding does seem to have short-term benefits for children and both short- and long-term benefits for mothers (well of course journalists aren’t known for their nuance, but still).
So don’t get me wrong: I think it is super important to have real and reliable data in order to create recommendations for breastfeeding and whether or not we should encourage women to do so. I recognize that starting to breastfeed can be a huge struggle and it is important to have the right information. But I feel that the societal debate that is happening following the publication of this article misses these points A LOT.
Is Breast Truly Best? Estimating the Effects of Breastfeeding on Long-term Child Health and Wellbeing in the United States Using Sibling Comparisons. Cynthia G Colen, David M Ramey. 2014 Social Science & Medicine, available online Jan 29 2014