Stanford, CA—When asked by postmenopausal women whether hormones are likely to affect their thinking and memory, pharmacists now can provide a current answer: Despite conventional wisdom, at least one type of estrogen therapy doesn’t appear to have much effect on those cognitive abilities, and it doesn’t seem to matter whether the hormones are used shortly after menopause or much later.

The research, published online recently by Neurology, is among the first large, long-term clinical trials to examine the cognitive effects of estradiol on women both at menopause and long after.

A widespread belief, according to background information in the article, is that estradiol benefits memory and thinking in women soon after menopause but not later, in what is called the “timing hypothesis.” Studies have had inconsistent results, however.

“This study fails to confirm the timing hypothesis,” pointed out lead study author Victor W. Henderson, MD, MS, of Stanford University School of Medicine in California. “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, researchers classified 567 healthy women between the ages of 41 and 84 into early and late groups, with the early group beginning therapy within 6 years of menopause and the late group starting at least 10 years postmenopausal. Participants took either beta-estradiol or a placebo pill every day, and those who had not had a hysterectomy also used a progesterone vaginal gel or placebo gel. With the average treatment duration nearly 5 years, cognitive tests were administered at the beginning of the trial, then 2.5 years and 5 years later to measure cognitive skills, including verbal memory.

Results indicate that no change in cognitive ability was associated with estradiol in either early or late postmenopausal women. In fact, compared to their starting scores, both groups of women generally improved in verbal memory due to practice. Study authors note that scores were the same for women with and without hot flashes, and for women who had a uterus and those who had undergone a hysterectomy.

“Estradiol initiated within six years of menopause does not affect verbal memory, executive functions, or global cognition differently than therapy begun 10+ years after menopause,” study authors conclude.

“Estradiol neither benefits nor harms these cognitive abilities regardless of time since menopause.”

Henderson cautioned 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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