Thursday, 27 February 2014

New breastfeeding research: approach with caution!

You may have seen this article in the Daily Mail, with the provocative headline:
"Breast milk is 'no better for a baby than bottled milk' - and it INCREASES the risk of asthma, expert claims". Having done some digging, including reading the abstract, extended abstract, press release and the full text of the scientific paper (Colen, C.G., Ramey, D.M., Is Breast Truly Best? Estimating the Effects of Breastfeeding on Long-term Child Health and Wellbeing in the United States Using Sibling Comparisons, Social Science & Medicine (2014), doi:10.1016/j.socscimed.2014.01.027. - available via ATHENS, or to purchase online) that this article is based on, and other reports, it's clear that the findings of this study should not be dismissed out of hand simply because they appear to contradict what we think we know about the long-term impact of breastfeeding on child health.

I recently heard scientific research described as 'like a jigsaw puzzle, except that there are no straight edges, and no picture to follow on the box' and thought that this was a useful way of thinking about it. Each new piece of research fits in somehow, but the how and where of it can take a long time to unravel. What's interesting, and what moves our understanding forward, is continuing to delve deeper, and, instead of dismissing results that we instinctively feel are 'wrong', asking 'How did the researchers obtain these results? Are their methods sound? Why did they get the outcomes they did? Are there clues in their work about other things we need to know before we can draw a sensible conclusion? Should we be acting to alter our recommendations or behaviour based on this research, or not?'

Of course, the above has nothing to do with the poor reporting of the research in the media (for interest, compare the Daily Mail article with this one for an illustration of how different two reports based on the same press release can be). My hackles rose at the line 'The NHS recommends that mothers breastfeed for around six months' - it doesn't, it recommends exclusive breastfeeding for around six months and continued breastfeeding alongside other foods after that, with no maximum duration specified. That the most basic of fact-checking hasn't been carried out makes me suspicious of reading too much into the Mail's slant on the story (that, and past experience of the Mail's anti- breastfeeding/anti-breastfeeding supporter agenda). Looking closer at the piece it follows the press release fairly closely, except that in certain telling ways it exaggerates the impact of this study, despite the authors taking care in their discussions to take a fairly moderate view. Something as simple as the Mail choosing to include a bullet point beneath the headline that reads "Dr Cynthia Colen says the benefits of breastfeeding are exaggerated", when in fact the press release says "A new study comparing siblings who were fed differently during infancy suggests that breast-feeding might be no more beneficial than bottle-feeding for 10 of 11 long-term health and well-being outcomes in children age 4 to 14." (my italics) serves to overstate the importance of this one study in the context of all the research into breastfeeding, artificial feeding and maternal and child health that is currently being carried out. Characterising Dr Colen as a generic 'expert' is another case in point; she's a sociologist, and an assistant professor - but what does this tag of 'expert', as applied by the Mail, mean? That she's more expert than other breastfeeding researchers? That she's the 'best expert' on breastfeeding that there is? There are plenty of other intelligent, committed, qualified researchers into breastfeeding currently working on research that may or may not support the findings of this paper - but the way the Mail uses the term 'expert' here suggests to the reader that this particular paper is somehow more important than others. I've talked before about the danger of believing that each new research paper moves everything 'forward' and it's helpful to remember it here - there are countless blind alleys and twists and turns in the quest for knowledge, and avoiding hyperbole when reporting new research would be a good start in making this more generally understood.

I've read the full paper and, I've got to confess, I am no statistician, so I am not best-placed to comment on whether the methodology is robust. At first glance, as an interested lay-person, it seems like a useful study, carefully designed to address some of the difficulties of previous studies, with some interesting results. The questions that immediately sprang to mind as I read it, which I would love others to examine in more detail, were the fact that the sample size of the differently-fed siblings was small - could it be that the numbers aren't sufficiently powerful to show statistical significance? I also wondered about breastfeeding duration - the researchers asked whether breastfeeding was initiated, and how long (in weeks) it went on for, but I couldn't find any numbers for this in the paper - what was the mean duration of breastfeeding in these families where one child was bottle-fed and one child was breastfed? If we are talking about the difference between two months or less of breastfeeding and bottle-feeding from birth, I would expect the results to show less of a difference than if we were comparing six months, or a year of breastfeeding against bottle-feeding from birth (based on the research I've read that shows a dose-response effect of breastfeeding on infant health). I found myself wondering about the scenarios in which one child in a family is breastfed and the other bottle-fed and how those might appear in these statistics - a common scenario in our culture of infant feeding in the UK, which I come across regularly as a breastfeeding peer supporter, is that a mother tries breastfeeding with her first baby, stops early due to a lack of support, then doesn't 'put herself through all that again' with subsequent children. I also wondered about whether the results of this study could be extrapolated to the UK or other Western cultures - the Mail certainly seems to think they can, as it was very unclear in their article that this was actually a US study (despite it being clear in the title of the paper itself). Differences in the racial and socioeconomic profiles of our respective societies might be important (indeed, the researchers note that one of the features of the differently-fed group is that the racial profile is different from that of the other two comparison groups, with the highest proportion of black/Hispanic families - although they urge caution in attaching too much significance to this).

Something else that was interesting to me is how the authors of the paper position themselves in terms of the research and debate surrounding infant feeding. In the introduction the authors write:
"Scientifically, disparities in infant feeding practices raise the critical question of the degree to which unobserved heterogeneity between children who were breastfed and those who were not may be driving the frequently noted positive association between breastfeeding and a wide variety of childhood outcomes. If this is the case, a well-intentioned, narrow emphasis on breastfeeding promotion would, at best, fail to realize positive benefits and, at worst, be a source of oppression for women who do not nor cannot breastfeed." (my italics)
This all sounded familiar to me and there's a reason for that, which becomes clear at the end of the paper:
"A truly comprehensive approach to increasing breastfeeding in the U.S., with a particular focus on reducing racial and SES disparities, will need to work toward increasing and improving parental leave policies, flexible work schedules and health benefits even for low-wage workers, and access to high quality child care that can ease the transition back to work for both mother and child. Hopefully, this multifaceted approach will allow women who want to breastfeed to do so for as long as possible without promoting a cult of “total motherhood” in which women’s identities are solely constructed in terms of providing the best possible opportunities for their children and the risks associated with a failure to breastfeed are drastically overstated (Wolf, 2011)." (my italics).
I think this at least sets the paper in context (for more, see my previous post about Joan Wolf). I should have guessed from the clue in the title of the research paper, 'Is Breast Truly Best?', which itself echoes the title of Wolf's book.

Let me be clear - I'm not dismissing the results of this paper. But just as its authors urge caution about overstating the benefits of breastfeeding in order not to oppress women, I urge caution about the importance we attach to the findings reported here, and suggest that we view them instead as one small piece of a very large jigsaw, and as a point of departure for asking further important questions.









25 comments:

  1. I love how the obvious is ignored by most researchers - how can something that is manufactured in a factory possibly be better than what our bodies evolved to do over millennia? Because historically there's far more evidence for human milk to be best for humans than there is for formula, as evidenced by the fact that our species didn't die out, and by the fact that prior to the advent of formula, a wet nurse was preferable and had better infant survival rates than feeding with milk from goats or cows.

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    1. Breastfeeding needs to be a personal and private choice. Just as with whom we have a child is and when in our lives we choose to do so. So many critical variables are being ignored and denied in the medical/political community. It is astounding.

      1. What is the true rate of alcohol and/or drug use (over the counter or otherwise) in breastfeeding mothers? Do we *really* know the long term affects are of that?

      2. Isn’t the mother’s overall health before, during, and after the pregnancy critical to this discussion for whoever is driving this seemingly irrational discussion?

      3. Why hasn’t the focus been placed on maternal nutrition during pregnancy? How *exactly* could this have less importance than whether or not to breastfeed post-pregnancy.

      4. Some mothers (including myself) are sensitive to hormonal shifts that have somewhat severe side effects during both pregnancy and breastfeeding—a bit like having PMS for several years, every day. What about people like this? Like me?

      5. Some babies just aren’t as good at breastfeeding for whatever reason, one of my babies (both full-term) was an immediate “breast feeder” and the other was not… However, both of my children were extremely healthy babies and children. Very bright students. Well adjusted human beings. Happy and healthy—never overweight nor failed to thrive at any point.

      Thank Goodness I went through my pregnancies 20+ years ago, before this very toxic, judgmental and intrusive policy became the norm.

      We are doing a great disservice to the mothers everywhere who are made to feel anything except DELIGHT to leave the hospital post delivery with their new baby. Instead they are pressured to feel like failures for not choosing to breastfeed constantly and tremendous shame for feeling uncomfortable about pumping breast milk after returning to work.

      Do children grow up happier or healthier if their mother’s feel inadequate from the very first day? Hmm… How could there be so many professionals so severely misguided?

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  2. The cult of motherhood? Please give me strength. This paper oppresses women and lets down a generation of women. The language " do not nor cannot breastfed" summarises the authors understanding of breastfeeding.
    I'm glad to find and share your post

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    1. Thank you! I enjoyed your response too :)

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  3. The researcher does not know if the babies were breastfed exclusively and I didn't see duration included either.

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  4. Nobody seems to also consider how well nourished the bf mothers were. Nor whether they were vegetarian. This SAD leaves much to be desired. Comparing ff with vegetarian bm, or ff with well nourished (WAPF style) bm must reveal differences.

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    1. No - there is no evidence that maternal levels of nutrition affect the ability of breastmilk to nourish in any way. In any case, this study would not be affected by this, as it was looking at babies from the same families. Please don't perpetuate the myth that mothers need to eat/drink certain foods in order to breastfeed.

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    2. Thanks for commenting and straightening this out Heather!

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  5. In evaluating the validity of a scientific study, one of the criteria is whether it is at odds with other studies on the same subject. If it is, as this is, it should be taken with a grain of salt.

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  6. Nutri Baby UK, you're suggesting that all vegetarian bf mothers are malnourished and their breastmilk is inferior to that of meat eating mothers or even formula based on a single aspect of their diet?!

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    1. Exactly! Chimps seem to manage really well

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    2. I wasn't suggesting that, no.

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  7. "Hopefully this study will give women who can’t or don’t want to breast-feed for whatever reason more ammunition to tell the breast-is-best purists to piss off"

    This last comment of the article says it all. Whoever wrote was obviously not a breastfeeding mother and is harboring some guilt or anger at their choice. Look hard enough and you can find research to support whatever belief you hold true.

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  8. Can we say study was funded by whom? My money would be on Ross Laboratories or Nestlé. Oh, my.

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    1. Thanks for commenting. I don't think there's any suggestion that this study has been funded by vested interests; according to the press release: "This work is supported by a grant from the Eunice Kennedy Shriver National Institute of Child Health & Human Development awarded to the Ohio State University Institute for Population Research."

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  9. It is interesting that the population which had differently fed babies also had a higher proportion of hispanic families. My understanding was that most hispanic mothers use "los dos" feeding which combines breastfeeding with formula. The proportions change as the baby grows. So in the study, "los dos" feeding would be classed as breastfeeding. Since it might not refer to any exclusive breastfeeding, I would not expect to see any difference between siblings who fed using this method vs fully or mostly formula fed.

    I would be intetested to see replication of the study analysis and results too,before anyone gets carried away.

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    1. This is interesting, thank you for commenting!

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  10. As RN working for many years in Obstetrics I studied and taught parenting classes. I also was involved in teaching nutritionally healthy life styles for a physician. I worked at keeping up with the latest research so I could advise our mother's wisely. That was years ago and I still find science interesting and want to keep up with the latest findings. The problem is the research findings change sometimes due to the researchers trying prove what they already believe. Like the research that women who smoke have babies of lower birth weight. I would consider that pregnant women who smoke would most likely make many other unhealthy choices. If my grand-daughters asked my opinion I would want them to consider how many people are involved in the production of formula. We get food recalls on a frequent basis. They found years later that a very popular formula actually caused severe problems for infants. There was an outrage when the company sent the formula they couldn't sell to a impoverished country. Some mothers have difficulty in breast feeding and the stress involved is not good for the baby or the family. Working mothers also have problems that should be considered. I do believe the best and safest milk is from the mother and leaving outsiders from being involved. It also is a great bonding time for them. That being said we need to realize there are circumstances where breast feeding is too difficult for some, and it does appear there are many that were not breast fed that are enjoying life,

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  11. This explains how the methodology was flawed - importantly, breastfeeding seems to have been defined as any breastfeeding, so could have been just one feed! http://info.babymilkaction.org/news/campaignblog280214

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  12. Good critical observation n analysis..:) thanks!

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  13. A small sample group is an obvious concern. Due to my personal experience i find this research very interesting. I bf my first exclusively for 6 months. She had 24 lots of antibiotics for chest infections before her 2nd birthday.She has since been diagnosed with asthma. I was unable to Bf My second and she has not had any chest infections. What I struggled with was the pressure and guilt to bf (some of it self imposed). Its about personal choice… so long as the baby is flourishing and the mother is happy. Surely this is best!

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  14. Trouble is, saying 'it's personal choice' ignores the fact that many women are not happy to be formula feeding, and sidesteps the way we need a whole culture to enable more breastfeeding. Surely it's better to work out ways of ensuring more of the women who want to breastfeed actually do it, while supporting the ones who don't, with no judging?

    Sounds as if you would have liked to breastfeed 2nd time, if you'd been able to, yes? It wasn't 'personal choice' with you, from the sound of it.

    Your experience with chest infections etc says nothing except that the outcome of individual cases cannot be predicted!

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  15. I think critically that this study was done "within" families. It is now well now that the environment can have a significant affect on a child's outcomes. By working "within" families this doesn't control for different environments. This I think casts a considerable shadow over the results and I would be interested to be directed in study that looks "between" families to see if the results differ. I think you might find they do.

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    1. That should say "well known" in the first line! The penultimate line should say "directed to a study". Problems with my keyboard!

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