Women with a longer fertile lifespan (the time from first menstruation to menopause) have a lower risk of the neurological disease, according to the findings released Wednesday and scheduled to be presented at the American Academy of Neurology's annual meeting in late April in Seattle.

Women who had hysterectomies (known as "menopause from surgery") had nearly double the odds of developing Parkinson's if they had used hormone therapy before surgery, compared to if they had never taken hormone therapy. No change in risk was apparent for those who used hormone therapy during their natural menopause.