On 15/05/2012 21:22, Sara wrote:
> Norma, I enjoyed seeing your daughter's calming words and demonstrations.  But I gotta ask about the news commentator's statistics:  'every year you bf your baby your risk of breast ca goes down by 32%"?  From what baseline?  The previous year's risk?  So there's diminishing gain with increasing years nursed?  It can't be a static benchmark because, um, after 3 years you what, give breast ca to the baby?<not very funny joke>  - What I'm asking is, how does this work?  What are the statistics?
Uh, I'd question his figures, for starters. As I understand it, the 
Lancet meta-analysis at 
http://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2802%2909454-0/fulltext 
is considered to be the most definitive study on the subject in terms of 
research quality, and they found a reduction of risk of 4.3% per year of 
breastfeeding. But, yes, whatever percentage reduction it is is from the 
baseline of where that year started, if you follow. (So, if we take 4.3% 
as the reduction per year, then one year of breastfeeding would reduce 
your risk by 4.3%, the second year would reduce your risk by 4.3% of the 
remaining 95.7% which is 4.1%, the third year would reduce your risk by 
4.3% of the remaining 91.6% which is 3.94%... etc.)


Best wishes,

Dr Sarah Vaughan (hoping that made some kind of coherent sense!)
MBChB MRCGP

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