The study included over 4,600 women. Approximately half of the women had at least one ovary removed before the onset of menopause and the other half were a control group of women who still had both ovaries. They found that having an ovary removed before menopause doubled the risk of developing Parkinson’s.
Age was also a factor in determining the risk of having at least one ovary removed and the increased chance of developing Parkinson’s disease. The younger a patient increased the probability of developing Parkinson’s, however hormone-replacement therapy (until the age of 50-55) reduced the risks when a single ovary was removed. Ironically beyond the age of 55-60 hormone-replacement therapy can itself increase the risk of developing cancer or a stroke.
The researchers feel that before a woman has an ovary removed she needs to discuss the latest research with her doctor. Their research also suggest that young women who have only one ovary removed need to be carefully monitored for low estrogen.