Question

Why do blind women have roughly half the breast cancer rate as sighted women and why does this difference decrease with age?

Answer 1

I believe it has to do with melanin production. Individuals who are blind produce less melanin than individuals who are sighted, less melanin means less melanin to grow rapidly / abnormally = less cancer risk.
And over time even sighted individuals produce less melanin. That's why the elderly are more likely to sun burn or develop skin cancer. So their numbers would be closer to the numbers of individuals who are blind.
Granted, this is purely a guess.

Answer 2

I dont know anything bout melanin and its risk factor but oestrogen is a factor, the longer you have it the higher the risk factor, women who menstruate early have increased risk. therefore the difference in blind women closes up to sighted over the years on top of melanin possibly, also breast feeding and kids decrease your risk

Answer 3

But how is estrogen and having kids different between sighted and nonsighted women? Both women have these comparatively equally.

Answer 4

I know, im just stating another risk factor, adding knowledge.
Heres some studies you can read if it helps
http://www.ncbi.nlm.nih.gov/pubmed/19649715
http://www.ncbi.nlm.nih.gov/pubmed/1591073
http://jnci.oxfordjournals.org/content/93/20/1513.full

Answer 5

Wow - nice find, BiomedStudent.

Answer 6

Thanks all, I heard it on the radio this morning and much appreciate the refs.

Answer 7

No bother blues, and kma230 ive been researching Evacetrapib, assays, stains, blood typing etcetc as part of my course, its gotten surprisingly easy to find stuff now, college is paying off XD