My understanding of the PROBIT study -- and I would very much like to
hear from those who know better if I'm wrong about this -- is that it
was never designed or intended to compare an exclusively-breastfed
group against a non-exclusively-breastfed or non-breastfed group.
Rather, it compares a large group cared for in Baby-Friendly hospitals
against a similar group cared for in non-Baby-Friendly hospitals.
(And perhaps there was some additional breastfeeding education/support
offered post-discharge to the Baby-Friendly group -- I can't
remember.)

When you compare breastfed against non-breastfed infants and look for
differences in ear infection rates or IQ points or obesity or
whatever, then your study will always be vulnerable to the charge that
it isn't really *breastfeeding* that made the difference, but rather
that the parents who tend to breastfeed also tend to have more money,
better health, a higher IQ, less obesity, etc etc etc.  The way to
avoid this charge, of course, would be to take two large and identical
groups of people and randomly assign one group to breastfeed and one
group to not breastfeed.  However, this is neither possible nor
ethical, so it has never and will never be done.

The PROBIT study, however, comes close to this kind of
"random-assignment" research design, except that what divides the two
groups is not breastfeeding per se, but Baby Friendly care in the
hospital.  My guess is that this was done in Belarus largely because
it was a country with a nationally-uniform hospital system that was
willing to make some (randomly selected, I hope) hospitals Baby
Friendly while leaving some other hospitals alone for the duration of
the study.  Perhaps there were other countries where this condition
could have been met, but perhaps not.

So, in the PROBIT group that was cared for in Baby-Friendly hospitals,
there were more babies who ended up being optimally fed than in the
control group ... though not all of them were, obviously.  But at
least when the study compared the Baby-Friendly group with the control
group and found that the first group had better health outcomes, those
findings weren't vulnerable to the charge that this happened because
parents who happen to breastfeed are different from those who don't.
The two groups are all the same in terms of education, socioeconomic
status, race/ethnicity, presence of misinformed grandmothers at home,
etc etc etc.  The *only* difference between the two groups is exposure
or lack of exposure to institutional delivery of
breastfeeding-supportive care and information.

If I'm right about this -- and again, if I'm wrong, I would really
love to hear from folks who are more knowledgeable -- then the
remarkable thing about this huge study is not that it didn't find
differences between the two groups of ALL the amazing ways that we
know breastfeeding is good for people.  The remarkable thing, in my
opinion, is that it found measurable differences at all.  And it did.

--Rebecca N. Ruhlen, LLLL, PhD, IBCLC
Davidson, North Carolina, USA

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