Hi Heather,
Yes this study was actually published a few weeks ago, I'm not sure why it is only now getting press. I agree, it is not an easy paper to read. SOme of that difficulty is inherent to the type of paper, but better writing could have made things clearer. 
The phrase you quote doesn't mean that there was a 29% difference between breastfed and non-breastfed children but that the *difference* between breastfed and non-breastfed children decreased by between 69 and 29% when sibling comparisons were used. 
The methods is particularly unclear, how much of the data is never vs ever breastfed comparison is an important thing to know and this cannot be determined.
Karleen Gribble
Australia
On 27/02/2014, at 4:42 AM, heather wrote:

>> I looked at this a while ago Heather. From memory it suffers from comparing never vs ever breastfed (it's quite a difficult paper to read and the methods are not very clear). And they selectively cite from the PROBIT study.
>> Karleen Gribble
>> Australia
> 
> 
> Thanks, Karleen, but it is a newly published study, apparently, and the (not very clear) article I linked to states "For each sample, the researchers sought answers to two basic questions: Was at least one child breast-fed and, if so, what was the duration of breast-feeding?"
> 
> The researchers looked at children aged 4 to 14 years old and some of the measures examined included aspects which you would not really expect bf to have a measurable impact - hyperactivity and digit recognition???
> 
> Some of the report is hard to understand:
> 
> "Some examples of differing benefits: Breast-feeding's beneficial influence on BMI decreased by 66 percent between siblings across families and siblings within families. The magnitude of the beneficial effects of breast-feeding for math, reading, vocabulary and intelligence declined by between 69 and 29 percent, respectively, when comparing data across families to data from within families."
> 
> Er...well, that's as clear as mud:( :( ....but if bf makes a 29 per cent difference (whatever that means....) between siblings,  then that's pretty significant, isn't it?
> 
> (A kind lactetter has just forwarded me the whole paper so I will look at it properly)
> 
> Heather Welford Neil
> NCT bfc, tutor, UK
> -- 
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