Scientists at the mayo clinic studied two groups of premenopausal women. One group had both ovaries. The others had undergone surgery to remove at least one. Those women had a 68 percent higher chance of developing symptoms of Parkinson's.
Researchers believe the premature drop in estrogen caused by removing the ovaries may be to blame.
Previous research has found that estrogen protects the brain's neurons and reduces the risk of Parkinson's.