Friday, May 31, 2013

Proving the Benefits of Breastfeeding

Breastfeeding might help lower a women's blood pressure for decades. Researchers at the University of Western Sydney School of Medicine couldn't help but notice (in their pile of data) that women who reported breastfeeding also had lower blood pressure. Then they set about to get proof breastfeeding actually lowers blood pressure according to Science News Report:
To prove their hypothesis, researchers examined the relationship between breastfeeding history and the occurrence of high blood pressure in 74,785 Australian women. These participants belonged to the age group 45 years and older. Researchers worked on data taken from the 45 and Up Study. This is a large scale study of healthy aging involving over 260,000 men and women in NSW. Breastfeeding Lowers Risk of Mothers Developing High Blood Pressure via Babble
Oh my. Science at its best...cough cough? Or science writing at its best? Let's hope the researchers set out to test rather than to prove their hypothesis. But from what I've learned thus far, it's a little bit of both.

In any event, let's think about the women here aged 45 and "up" - some several decades older than 45.  How rare do you think it was for those older women to breastfeed back 30, 40, 50 years ago? Do you think they might have been more health-minded than their peers? Me thinks these are not your average semi-sedentary coffee and donut seniors.

Thank you Babble for keeping us informed about the benefits of breastfeeding. In next week's news... how breastfeeding can make you live 10 years longer, have better sex and earn more money.

6 comments:

Sarah said...

Nice post. I was curious about the actual study these articles are referring to, since neither one appears to link to it directly, and unless I'm mistaken this seems to be it:

http://www.ajog.org/article/S0002-9378(13)00155-5/fulltext

Interestingly, the study says this:

"Women who breastfeed may therefore represent a healthier cohort. From our data it is not possible to determine whether women who breastfed were a healthier cohort during their childbearing years, or whether breastfeeding results in healthier behaviors beyond a woman's childbearing years."

But for some reason, that doesn't stop the authors from also saying things like this:

"Women should therefore be encouraged to breastfeed for as long as possible to reduce the likelihood of high blood pressure before 64 years of age."

I don't understand how these researchers can find a correlation (based on a self-reported survey apparently), acknowledge the possibility of an important confounding factor, and yet feel justified in making such sweeping health claims and recommendations. Am I misunderstanding something? Is this sort of thing considered acceptable practice in other areas of scientific research?

Polly Palumbo, Ph.D. said...

Thank you, Sarah! You are not misunderstanding a thing here. In fact you've nailed it. This study is more lame than the usual breastfeeding fare but hardly unusual in the literature. I find the possibility that breasfeeding a baby somehow embued women with the motivation/courage/ability/super powers to live a more lifestyle for decades. I mean, that statement should have been axed. To their credit the authors do suggest some sort of physiological, possibly hormonal-related changes associated with breastfeeding that might impact blood pressure. But on top of the other ridiculousness it's hard to take it seriously (at least from this crusy self-reported retrospective data).

As for other realms, I think it really varies. There are claims that as many as two-thirds of the better quality research (i.e. in top journals) either gets dismissed outright by later studies or never gets replicated despite attempts - meaning, is to some degree probably not quite right.

Polly Palumbo, Ph.D. said...

Thank you, Sarah! You are not misunderstanding a thing here. In fact you've nailed it. This study is more lame than the usual breastfeeding fare but hardly unusual in the literature. I find the possibility that breasfeeding a baby somehow embued women with the motivation/courage/ability/super powers to live a healthier lifestyle for a few decades absurd. To their credit the authors do suggest some sort of physiological, possibly hormonal-related changes associated with breastfeeding that might impact blood pressure. But on top of the other ridiculousness it's hard to take it seriously (at least from this crusy self-reported retrospective data).

As for other realms, I think it really varies. There are claims that as many as two-thirds of the better quality research (i.e. in top journals) either gets dismissed outright by later studies or never gets replicated despite attempts - meaning, is to some degree probably not quite right

Chip said...

Polly,

Is there a core of research that you find generally convincing as to the net benefits of breastfeeding -- for children? The claim is repeated as gospel, but it seems that every study I see touted in the media is fraught with confounders.

Polly Palumbo, Ph.D. said...

Chip, I hear you on the gospel part.There are better controlled studies (as in more confounds) in the literature. I think the findings involving ear infections, respiratory infections and gastro problems are the more convincing of the lot. The SIDS, diabetes, obesity, IQ claims...highly problematic. I do believe there are moderate, short-term (if not long-term)benefits. But I agree too many are fraught with confounds and they simply go without questioning in the media and the health community.

Polly Palumbo, Ph.D. said...

There's another issue, Chip, beyond methodological short-comings - publishing bias. When's the last time you heard about a study that found no benefits to breastfeeding?