The Corpus Callosum

I'm sitting here, wondering why in the world I wrote so much about a topic that is of no more than passing interest to me.  Perhaps if I keep writing, I will figure it out.

Note: this will not make much sense unless you've already read Janet's more recent post on the topic of breastfeeding, here: What are the real benefits of breastfeeding? Statisticians weigh in.  You also have to have read the main article she cites, here: What Science Really Says About the Benefits of Breast-Feeding (and what the New York Times didn’t tell you).

This is the comment I left:


OK, I've read the article by Goldin et. al., and I have a few comments.  First of all, I am not a statistician, and I habitually get in the back seat when a statistician speaks about research.  However, I am not happy with the depth of their analysis.  

First, in order to make a pronouncement about the entirety of the literature on a subject, one would have to gather all the relevant articles and read them.  I do not see any evidence that they have done so.  One would have to rank the studies in terms of quality.  The date of the study is one factor, but it is not really a measure of quality.  Maybe they did all that, and did not tell us, but I don't think we can be confident in their conclusions without knowing.

Second, I have to give them credit for finding evidence that some of the people involved in this might be biased.  That is important to know.  But it is circumstantial, and does not really help us get to the truth of the matter.  It only cautions us to look more closely at the research methods.

Furthermore, their own article is not free of evidence of bias.  For example, they write rather dismissively about the seriousness of the illnesses: "if the only adverse consequence of not nursing is that babies get a few more colds..."  They do not mention necrotizing enterocolitis, which has a significant mortality rate.  [See especially: Lucas A, Cole TJ: Breast milk and neonatal necrotising enterocolitis. Lancet 1990 Dec 22-29; 336(8730): 1519-23.]

Finally, they conclude with this:

Our lives are filled with risks, small and large. Not nursing is a small risk, the real question is what it costs (or benefits) you.

That is true.  However, consider that every single person on the planet has either been breastfed, or not.  That being the case, whatever risk you find, no matter how small, has to be multiplied by six billion.  Take a small number and multiply by six billion, and the product just might turn out to be significant.  

The authors point out, correctly, that a full analysis of the topic would be highly complex.  They are critical of the AAP for being too casual in their analysis.  Then they toss another casual analysis on the heap.  

Perhaps they are correct in saying that an important public health announcement should have a stronger scientific basis.  But it would be more helpful if they would go on to say how the science could be strengthened, e.g. by a Cochrane review of the existing data...

...and, as it turns out, there is a Cochrane review that is pertinent, albeit not comprehensive; it only examines a narrow piece of the overall question.  Among their conclusions:

Infants who are exclusively breastfed for six months experience less morbidity from gastrointestinal infection than those who are mixed breastfed as of three or four months, and no deficits have been demonstrated in growth among infants from either developing or developed countries who are exclusively breastfed for six months or longer.   

If a careful review of 2,668 unique citations leads to a conclusion that exclusively-breastfed infants do better, then I think we need to pay attention.  Granted, it is not a comprehensive analysis, but it also is not "just a throw back public health campaign based on voodoo science."

I'll agree with them that some of the studies cited in the New York Times are insufficiently rigorous.  But if what we are trying to do is get a fair and balanced look, then let's take a look at the studies that are rigorous.


Let us also note that the WHO has been looking at this issue very closely, and at least mention the fact that they have consistently come out in favor of breastfeeding.  Granted, the WHO is not a scientific agency; it is a political organization.  Whatever their agenda, though, at least it is not an economic one.  As far as I can tell, their motivations are purely humanitarian.  That is not the case with some of those who have a say in this. From a WHO publication, Evidence for the Ten Steps to Successful Breastfeeding (link opens PDF):  

Reiff & Essock-Vitale (1985) reported a survey in a university hospital in the United States of America (USA) where most official policies, educational materials and counselling and support programmes promoted breastfeeding. However, there was no policy to limit the use of infant formula, and a single brand of ready-to-use infant formula was used daily in the maternity ward. In the delivery room 66% of mothers had stated a preference for exclusive breastfeeding but when interviewed at 2 weeks only 23% were breastfeeding without formula supplements.  93% of the mothers using formula at 2 weeks knew the name of the hospital brand and 88% were using it.

But I think what really interests me about this topic is something that is not immediately obvious.  The authors of the Goldin et. al. paper wonder if the campaign to increase the frequency of breastfeeding is "just a throw back public health campaign based on voodoo science."  

That question raises an issue that I think deserves some attention: how much evidence do we need regarding the health effects of a given intervention, before it is worth having a government-sponsored ad campaign?

Clearly, since breastfeeding affects a large number of people, even a small health benefit could have a highly significant impact.  Equally clearly, if we wait until the evidence is incontrovertible, we potentially loose an opportunity to have a large, positive impact.  Goldin et. al. entirely miss the point with their closing sentence:

Our lives are filled with risks, small and large. Not nursing is a small risk, the real question is what it costs (or benefits) you.

No no no.  A public health campaign is NOT about what benefits a given individual.  That is a question that only the individual can decide.  I am not disputing anyone's right and responsibility to make an independent choice.  But that is not the point at all, when it comes to public health.  The point of public health is to improve the average health of the population.  Yes, some people may be inconvenienced; some may even face serious risks.  

This is not a new argument.  The same point has been debated ad nauseam with regard to vaccinations.  Vaccinations can -- and do -- result in serious problems, including death.  But we routinely ask people to accept a small risk of death from the vaccine, in exchange for improved health of the population.  Sometimes we make mistakes, as was the case with the swine flu vaccination program in the 1970's.  But the alternative is no vaccinations, since we do not know and can not know, ahead of time, which programs will turn out to have been worthwhile.  

There is an ethical question with regard to public health campaigns.  That question is the one that is at the root of ALL ethical questions: who gets to make the decision?  In the case of vaccination, a case can be made for compulsory vaccination, if the evidence is strong enough.  If the evidence is less strong, then compulsion is not justified, but influence may be justified.  

The government campaign to promote breastfeeding is not intended to force anyone to do anything.  It is intended to have an influence on the behavior of a proportion of the population.  So this is not really an ethical issue, so much as it is a policy issue: does it make good economic sense to promote a behavior that has some evidence of benefit?  How much evidence do we need to have, before such a program is warranted?  

There are ethical questions lurking in there: Who gets to decide how much evidence is enough? and, Who gets to decide if the evidence for the health benefits for breastfeeding meets the standard?  Keep in mind that if we debate those questions until everyone is satisfied, we'll never get anything done.  If your goal in life is to do nothing, then fine, debate all you want.  I would argue, though, that at some point, it is time to actually do something.  

Here we have situation in which the American Academy of Pediatrics and the World Health Organization both support the position in the campaign.  The most comprehensive, systematic literature review that I could find, is consistent with the message in the campaign.  Isn't that enough?

If you've had the patience to read this far, you might be interesting in this exercise in Darwinian medicine: Association of atopic diseases with breast-feeding: Food allergens, fatty acids, and evolution. J Pediatr. 1999 Jan;134(1):5-7.