HIV and Breastfeeding Study Broken Down

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Monday, April 23, 2007

Back in March I wrote a post talking about the push for HIV positive moms to breastfeed on the premise that a new study showed that exclusively breastfed infants were less likely than babies that also received formula or early solids to contact HIV from their HIV positive mothers.

At the time, I wrote:

So knowing that breast milk is the BEST form of nutrition, but that formula is extremely likely to result in a healthy baby as well...

Why in the WORLD would you encourage a mother to risk a 4% transmission rate of a disease that kills every single person that contracts it? When the risk of death from using formula is far, far lower than that?

It's called the risk/reward ratio people.

So could someone please explain to me how the 4% risk of HIV transmission is worth the reward of what breast milk gives? Sure, it's great for that 96% of babies that end up healthier and HIV free...but what about that 4%?

I was basing that information off of the news reports that I could find on the study. Quite honestly, I was (and remain) astounded that so many lactation professionals are on email lists pushing exclusive breastfeeding for the children of HIV positive mothers without limiting that suggestion to those in third world countries.

Today, I ran across an article on Stats.Org that really breaks the HIV/Breastfeeding study down and points out a lot of the problems with the way the data has been represented in the media. Having read through this new post I'm even more convinced that no HIV positive mother with access to a clean water supply should be breastfeeding their child.

From the study:

The rate of HIV infection among breastfed babies is almost 20 percent. The four percent figure is among babies who were uninfected after six weeks. And the reduced risk attributed to breast feeding is compared to babies who also have formula, not compared to those who are exclusively formula fed.

The main issue with this study is that it is not comparing breastfeeding and not breastfeeding...

Note that first paragraph...the actual rates are 20 percent. That's quite a bit different from the four percent that is often touted by lactation professionals. Considering that contracting HIV is a death sentence, 20 percent is a pretty scary number. Also, the four percent rate applies only to those that remain uninfected by six weeks. That's great...if you can see the future and know that the child will not be infected, but unless mom plans to pump to maintain her supply for six weeks while giving the child donor milk, I just don't see how that figure really helps anyone.

She also points out a pretty serious problem with the credibility of the study...

The Lancet study was observational, not controlled. That is to say, the women were not told whether to supplement their breast milk with solids or formula or not: they were simply provided with the formula should they choose to use it. While in theory, those who decided to breastfeed exclusively and those who decided to do “mixed feeding” were similar groups of women, both sets of women were HIV-positive South African women with young children. But HIV infection does not affect all people equally at all times before the infection turns lethal. If the women who are sicker are also less likely to breastfeed alone, the whole data could be skewed.

How would the data be skewed if sicker women introduced formula into the diet of their babies? It could be that they have higher levels of HIV virus in their bodies and in their breast milk, which is then passed to the babies. It could also be that they are themselves immuno-compromised, which in turn diminishes the positive immunological effects of the breast milk that their babies do get. Yet another possibility is that there are other, secondary infections that these women suffer from – which, when passed to their babies, make the babies more vulnerable to the HIV exposure through breast milk. In all these cases, there would be no greater positive effect for their babies were these women to nurse exclusively.

The problem here is that no controlled study could ever be put together in this type of situation. It's unethical to make a mom nurse her child while HIV positive, so self-reported and observational style data is the only type that can be collected. I'm not statistician, but I do know that controlled studies are the most accurate and that many flaws present themselves when you aim to put together an observational study.

The final issue here is the one that I brought up in my original post. This study and the results were aimed at mothers and children that live in third world countries where clean water supplies are an issue. Here in the United States and in other developed nations, the risk of formula feeding is significantly smaller.

The two main factors leading to infant deaths in this study were illness resulting from poor water quality, and infection by HIV. Those who are given formula are exposed to the water (with an immature gut), while those who are given breast milk are exposed to the HIV virus. In making these comparisons, the study is trying to assess which of the two evils is lesser.

Both of these are different calculations for people living in North America and Europe. First of all, water quality is high and babies do not typically die of waterborne illness and associated diarrhea and dehydration. Over 70 percent of American babies are formula fed, with no indication that this has an impact on death rates (we noted last year that the American Academy of Pediatrics’ claim that using formula increases death rates was based on injury rates, not formula use).

So once again, I'd really like someone from the lactation community that still believes that babies who are born HIV free in developed nations should be breastfed and why because quite frankly, I cannot wrap my head around that line of thinking.

Labels: Breastfeeding Advice

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