Dementia Risk Linked to Ovary Removal
Dementia More Common in Women Who Lose Ovaries in Their 30s and 40s
One reason Norris is skeptical of the Rocca study is that removal of one
ovary had a much larger effect than removing both ovaries.
"Why are women with one ovary taken out doing worse than those with both
taken out? You have to raise an eyebrow about that," he says.
Rocca suggests that the situation is more complicated than most researchers
realize. He suggests that women who have the kinds of problems that result in
hysterectomy -- such as uterine fibroids or endometriosis -- have some
underlying defect in the way their bodies use estrogen.
In another study he presented at the AAN meeting, Rocca found that women
with Parkinson's disease tend to have defects in certain estrogen-related
genes. He suggests that women who carry these unusual genes may be at higher
risk of dementia -- and ovary removal simply magnifies this risk.
"So the game is more complex than just the issue of how much estrogen a
woman's ovaries are making," Rocca says. "We will at some point be
better able to advise the woman facing the surgeon and predict final balance
between the benefit of preventing ovarian and breast cancer vs. the risk of
dementia, Parkinson's disease, stroke, or heart attack. It is very complicated
-- but if what we are seeing gets confirmed by others, in the future we could
offer to the individual woman a more intelligent and informed basis to make a
decision on ovary removal."
Norris, however, says the Rocca study offers far too little evidence for
"I think he is out on a limb here," he says.