Ovaries out, dementia in?

            ROCHESTER, MN - Women who have their ovaries removed before menopause are at higher risk for memory problems or dementia and movement disorders such as Parkinson's disease, state two studies in the online edition of Neurology.

            The study on dementia involved approximately 1,500 women who had the removal of one or both ovaries for non-cancer-related reasons, such as ovarian cysts, endometriosis, or for the prevention of ovarian cancer. The women were compared to an equal number of women who still had both ovaries at the study’s start. All were followed for a median of 27 years and were interviewed about their memory. If the women couldn’t be interviewed, investigators interviewed a family member. Scientists found women who had one or both ovaries removed before menopause were nearly two times more likely to develop cognitive problems or dementia versus women who didn’t have the surgery. Women who were younger when their ovaries were removed were more likely to get dementia than women who were older upon removal.

            "It's possible that estrogen has a protective effect on the brain and a lack of estrogen due to ovary removal may increase a woman's risk of developing memory problems," said study author Dr. Walter A. Rocca, of the Mayo Clinic. He says this is one of the first studies to show there may be a critical age window for the protective effect of estrogen on the brain in women. Before this study, knowledge was based almost exclusively on animal tests. "For example, the study found women who had both ovaries removed before age 49, but were given estrogen treatment until at least age 50, didn’t have an increased risk of developing memory problems. The findings suggest that estrogen is protective for these women in this age window.

            By contrast, past studies from the Women's Health Initiative have shown estrogen use started at age 65 or later may have a negative effect on memory and may increase the risk of developing dementia," said Dr. Rocca. He says these findings have important clinical implications and should prompt physicians to reassess removing ovaries before menopause and the use of estrogen treatment following such surgery. "Although almost 60% of women received some estrogen treatment after both of their ovaries were removed, only 20% of them received estrogen treatment until at least age 50.  That is the median age when women reach natural menopause."

            Both studies were supported by grants from the National Institute of Neurological Disorders and Stroke and the National Institute of Arthritis and Musculoskeletal and Skin Diseases.