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New research suggests that hormone therapy taken soon after menopause may help protect against the mental decline of dementia, even though it raises that risk in elderly women.
The study adds yet another frustrating twist to the back-and-forth findings about whether hormone-replacement therapy protects against diseases of aging. Though the accepted answer has been "no" in recent years, the latest evidence suggests that timing of treatments may be key, at least for heart attacks and now for dementia.
"When you give it may be very important," said Dr. Sam Gandy, an Alzheimer's disease expert at Thomas Jefferson University in Philadelphia.
The new findings were released Wednesday in Boston at a meeting of the American Academy of Neurology. Experts cautioned that they are preliminary.
Lead researcher Dr. Victor Henderson, of Stanford University, agreed that it's too soon to consider putting younger women back on hormones to forestall dementia.
For decades, women routinely took hormones to treat the hot flashes of menopause and to ward off ailments of aging. Then, in 2002, a milestone study showed higher risks of heart attack, stroke, and breast cancer with estrogen-progestin treatments. Estrogen-only pills were later also linked to stroke.
As a result, millions of women gave up the pills, and government experts advised women to use them only for severe menopause symptoms and to take the lowest dose for the shortest time possible.
But in recent weeks, mounting evidence has emerged that women who take such drugs closer to menopause may get more benefit or confront less risk than women who start taking them later. An analysis this month indicated the drugs do not raise the risk of heart attack for women ages 50-to-59, and they seem to survive longer with the drug.
The latest findings focused on 7,153 women in an offshoot study of the huge Women's Health Initiative that tracked breast cancer and heart disease. The cognitive study was funded by the National Institutes of Health and by Wyeth, which sells hormone treatments.
Previous research showed that women who take hormones after age 65 experience a 75 percent increased risk of dementia over other women.
But this study found the opposite for women who took hormones before age 65: Dementia risk was reduced by nearly half.
Dementia developed in 22 of 2,228 women - or only 1 percent - who took hormones at the earlier time, but in 84 of 4,925 who did not - or 1.7 percent. The apparent protective effect was especially strong for Alzheimer's disease, a common form of dementia.
"It's an intriguing and biologically plausible finding ... but it needs to be confirmed," said Dr. JoAnn Manson, of Brigham and Women's Hospital in Boston, who helped research the Women's Health Initiative.
She said replacement hormones may preserve blood circulation in the brain.