BOSTON -; New research suggests that hormone therapy taken soon after menopause may help protect against dementia even though it raises the risk of mental decline in women who do not take the drugs until they are older.

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 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 also later were 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.