HORMONE THERAPY RESEARCH Estrogen raises dementia risk for older women

NEW YORK -- Older postmenopausal women who take estrogen significantly increase their risk of developing dementia, whether they take the hormone alone or combined with progestin, according to a study published in today's Journal of the American Medical Association.
A related study found that women 65 or older taking estrogen had slightly lower cognitive function, on average, than those taking a placebo -- a difference that emerged within a year or two of starting estrogen therapy.
The studies represent the first detailed analyses of cognitive function to include data from the estrogen-only arm of the Women's Health Initiative, a multiyear clinical trial of more than 27,000 women sponsored by the National Institutes of Health and Wyeth-Ayerst Research.
"It's clear from the findings that estrogen hormone therapy should not be used to prevent dementia -- it won't prevent it and in fact will increase the risk," said Stephen Rapp, co-author on both papers and professor of psychiatry at Wake Forest University School of Medicine in Winston-Salem, N.C.
Studies halted
The estrogen-only arm of the study (2,947 women taking estrogen or a placebo) was started in 1995 and halted prematurely in February because of concern about adverse effects, especially an increased incidence of stroke. The estrogen plus progestin arm (4,532 women taking the combination or a placebo) was halted two years ago because of increases in breast cancer, heart attacks, strokes and blood clots.
In an apparent attempt to assuage the fears of more than 4 million American women who still take estrogen, Wyeth Phamaceuticals released a statement saying the results may not be applicable to younger women who use estrogen to treat hot flashes and nightsweats. Estrogen is often prescribed to women who have undergone hysterectomy and are 42 on average, while estrogen plus progestin is prescribed to treat women who enter menopause naturally, generally around age 51. The U.S. Food and Drug Administration recommends it be taken at the lowest effective dose and for the shortest duration necessary.
An editorial in the journal held out the possibility that younger women who take estrogen during a "critical period" in early post-menopause may benefit from lower dementia rates later. Researcher Rapp called the suggestion "speculative."
"There are some who are having a tough time letting go of the idea that estrogen is beneficial," he said.
Much greater risk
The study found 28 women taking estrogen only were diagnosed with probable dementia, compared to 19 in the placebo group. The difference wasn't statistically significant, Rapp said. But when researchers pooled the results with those from the combination trials "the significance jumped right out at you: A 76 percent greater risk of dementia in the hormone therapy group."

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