"The risk is higher for women with both ovaries removed; however, it may also be somewhat increased when only one ovary is removed," says Walter Rocca, M.D., Mayo Clinic epidemiologist and lead study investigator. "In addition, there is a suggestion that for women with one ovary removed, removal of the uterus may also increase the risk."

Dr. Rocca emphasizes that his study's findings must be viewed by women contemplating an elective or preventive removal of the ovaries and uterus in consultation with their physicians in the context of a woman's medical history, her genetic makeup and other diseases or risk factors. He also stresses that physicians must carefully consider the age of the woman at the time of the surgery and the option of treating the woman after surgery with estrogen therapy.

"Like any medical or surgical decision, there is a trade between risk and benefit," says Dr. Rocca. "Our findings are important for situations where the removal of the ovaries is 'elective' -- that is, conducted to reduce the risk of ovarian cancer."

At issue with removal of the ovaries and parkinsonism risk is a woman's estrogen level. According to the Mayo Clinic investigators, removal of both ovaries is the major cause of reduced estrogen during a woman's fertile life, and this reduction is linked to parkinsonism risk.

"This is the first direct confirmation that reduced estrogen produced during adult life by the ovaries increases the risk of parkinsonism; this is also the first general population study addressing this question," says Dr. Rocca. "Removal of both ovaries directly eliminates the major source of estrogen." Even women who received est
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Contact: Lisa Lucier
newsbureau@mayo.edu
507-284-5005
Mayo Clinic
13-Apr-2005