You can do an encouragement design similar to what was done in Belarus by randomizing some hospitals to adopt breastfeeding-friendly policies and some to not adopt them. Unfortunately, since not all parents in a breastfeeding-friendly hospital will breastfeed and not all parents in a control hospital will use formula, and since you’re randomizing at the hospital level, your sample size has to be huge to detect any effect. And because many of the outcome variables you’re interested in are long-term (IQ age seven, for example), you have to follow people for a long time. It’s very very expensive and it takes forever.
The Belarus results are IMO the strongest results we have about the benefits of breastfeeding, and show a huge rise in IQ from three months of breastfeeding. Of course, as this post points out, the top formula brands have improved their product in the past decade, and modern babies may receive better milk than the babies of the Belarus study. ¯\_(ツ)_/¯
Ozy—sibling studies have a major problem—they don’t take into account the reasons why a mother would breast-feed one child but not the other. If you ask moms about this, they always have an answer, and it is usually something like, ‘Josh was very sleepy and just wouldn’t suck. We had to give him a bottle to get him to eat at all.’ My mother basically gives this exact story for why I was breast-fed and my brother was not. And my brother had developmental problems and I did not. I don’t think this is because he was fed formula. Remember, weaker/sicker babies are more likely to get formula, and sicker/older/tireder/more depressed mothers are more likely to formula feed. In order to breastfeed, everything has to go right. One thing goes wrong, and it’s on to formula.
I think the point here is that there are many circumstances that can influence the choice to use formula, and these might have a stronger effect than the choice itself.
But population-level differences in populations that were encouraged to breastfeed vs. not encouraged to breastfeed, as in the Belarusian study, should circumvent that.
“Sites were randomly assigned to receive an experimental intervention (n = 16) modeled on the Baby-Friendly Hospital Initiative of the World Health Organization and United Nations Children’s Fund, which emphasizes health care worker assistance with initiating and maintaining breastfeeding and lactation and postnatal breastfeeding support, or a control intervention (n = 15) of continuing usual infant feeding practices and policies.”
You can do an encouragement design similar to what was done in Belarus by randomizing some hospitals to adopt breastfeeding-friendly policies and some to not adopt them. Unfortunately, since not all parents in a breastfeeding-friendly hospital will breastfeed and not all parents in a control hospital will use formula, and since you’re randomizing at the hospital level, your sample size has to be huge to detect any effect. And because many of the outcome variables you’re interested in are long-term (IQ age seven, for example), you have to follow people for a long time. It’s very very expensive and it takes forever.
The Belarus results are IMO the strongest results we have about the benefits of breastfeeding, and show a huge rise in IQ from three months of breastfeeding. Of course, as this post points out, the top formula brands have improved their product in the past decade, and modern babies may receive better milk than the babies of the Belarus study. ¯\_(ツ)_/¯
Ozy—sibling studies have a major problem—they don’t take into account the reasons why a mother would breast-feed one child but not the other. If you ask moms about this, they always have an answer, and it is usually something like, ‘Josh was very sleepy and just wouldn’t suck. We had to give him a bottle to get him to eat at all.’ My mother basically gives this exact story for why I was breast-fed and my brother was not.
And my brother had developmental problems and I did not. I don’t think this is because he was fed formula.
Remember, weaker/sicker babies are more likely to get formula, and sicker/older/tireder/more depressed mothers are more likely to formula feed. In order to breastfeed, everything has to go right. One thing goes wrong, and it’s on to formula.
I’m confused—the Belarusian study Ozy is talking about wasn’t a sibling study, right?
I think the point here is that there are many circumstances that can influence the choice to use formula, and these might have a stronger effect than the choice itself.
But population-level differences in populations that were encouraged to breastfeed vs. not encouraged to breastfeed, as in the Belarusian study, should circumvent that.
Correct. I guess I’d rather have an appropriate quantification of the “encouragment” though; but I could be wrong, I will read the study design...
“Sites were randomly assigned to receive an experimental intervention (n = 16) modeled on the Baby-Friendly Hospital Initiative of the World Health Organization and United Nations Children’s Fund, which emphasizes health care worker assistance with initiating and maintaining breastfeeding and lactation and postnatal breastfeeding support, or a control intervention (n = 15) of continuing usual infant feeding practices and policies.”