Endogenous Estrogen May Protect Women from Parkinson's Disease

A study conducted at the Albert Einstein College of Medicine of Yeshiva University has found that more years of fertility (time from first menstruation to menopause) translates to a lower risk for developing Parkinson’s disease in women.

Researchers analyzed the Women’s Health Initiative (WHI) Observational Study records of nearly 74,000 women who went through natural menopause. They found that women with a fertile lifespan of over 39 years had a 25 percent lower risk for developing Parkinson’s disease than women with a fertile lifespan of less than 33 years. Additionally, women with four or more pregnancies were 20 percent more likely to have Parkinson’s disease than women with three or fewer pregnancies.

"One explanation for this finding is that the post-partum period, which is typically one with lower levels of estrogen, subtracts from a woman's total fertile lifespan," said lead investigator and co-author Sylvia Wassertheil-Smoller, PhD, professor of epidemiology and population health.

The study suggests that “longer exposure to the body’s own, or endogenous, hormones, including estrogen, may help protect the brain cells that are affected by Parkinson’s disease,” said lead author Rachel Saunders-Pullman, MD, MPH, MS, assistant professor of neurology, attending physician in neurology at Beth Israel Medical Center.

"Overall, our findings might lead one to assume that hormone therapy would make sense as a neuroprotective agent," said Dr. Saunders-Pullman. "However, we also found that women who were taking hormone therapy did not have a lower risk for Parkinson's. Thus, our data does not support a role for treatment with exogenous hormones, that is, hormones that originate outside the body, to prevent Parkinson's."

Further details of the study are set to be presented at the American Academy of Neurology’s 61st Annual Meeting in Seattle, scheduled for April 25-May 2, 2009.