Public Release: 

Does hormone therapy after menopause affect memory?

American Academy of Neurology

MINNEAPOLIS - Contrary to popular belief, taking estrogen after menopause may not affect the memory and thinking abilities of healthy women no matter when the treatment is started. The research is published in the July 20, 2016, online issue of Neurology®, the medical journal of the American Academy of Neurology. The recent study is among the first large, long-term clinical trial to examine the cognitive effects of estradiol, a type of estrogen, on women both close to and long after menopause.

Millions of women take estrogen to treat hot flashes, night sweats and other symptoms caused by menopause. Estradiol is the main type of estrogen produced by women in their reproductive years. Previously, researchers thought estradiol benefitted memory and thinking in women soon after menopause but not later, called the "timing hypothesis". Prior studies testing the theory have not found consistent results.

"This study fails to confirm the timing hypothesis," said study author Victor W. Henderson, MD, MS, of Stanford University School of Medicine in California and a Fellow of the American Academy of Neurology. "Our results suggest that healthy women at all stages after menopause should not take estrogen to improve memory. At the same time, women need not particularly be concerned about negative effects of postmenopausal estrogen supplements on memory when used for less than five years."

For the study, 567 healthy women between the ages of 41 and 84 were classified into early and late groups. The early group was within six years of menopause and the late group was at least 10 years postmenopausal. Participants took beta-estradiol every day or a placebo pill. The women also used a progesterone vaginal gel or placebo gel, unless they had a hysterectomy. The average treatment duration was nearly five years. Cognitive tests were performed at the beginning of the trial, 2.5 years and five years to measure thinking skills including verbal memory.

The study showed that no change in cognitive ability was associated with estradiol in either early or late postmenopausal women. Compared to their starting scores, both groups of women improved in verbal memory due to practice. Scores were the same for women with and without hot flashes, and for women who had a uterus and those who had a hysterectomy.

Henderson noted that the study only addressed the effects of estradiol, just one type of estrogen, and did not examine its use in women with existing mild cognitive impairment or dementia.

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The study was supported by the National Institutes of Health. Study drugs and placebos were provided by Teva Pharmaceuticals, Watson Pharmaceuticals, Inc. and Abbott Laboratories.

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The American Academy of Neurology, an association of 30,000 neurologists and neuroscience professionals, is dedicated to promoting the highest quality patient-centered neurologic care. A neurologist is a doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system such as Alzheimer's disease, stroke, migraine, multiple sclerosis, brain injury, Parkinson's disease and epilepsy.

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