This is the VOA Special English Health Report.

New research has found another danger of hormone replacement therapy. The therapy studied involved the hormone progestin mixed with the hormone estrogen.

Women's bodies stop producing estrogen at about age fifty. This period of life is called menopause. Until recently, medical experts believed that estrogen and progestin could protect older women from heart disease, breast cancer and memory loss. But last year American researchers found that this therapy increased the chance of breast cancer and heart problems. The researchers halted a national women's health study early.

Now, related research shows that the same therapy increases the chance of memory loss and brain damage in women over age sixty-five. The study found two times the chance of the condition called dementia, compared to women who took an inactive substance. The Journal of the American Medical Association published the results. It also published findings of an increase in the chance of a stroke.

All these findings are from the Women's Health Initiative by the National Institutes of Health. This involved the largest and most scientific study ever done to test the effect of hormone replacement on disease prevention. More than sixteen-thousand women between the ages of fifty and seventy-nine took part. The research involved a drug called Prempro, a combination of estrogen and progestin.

The lead researcher of the new study says the results show there is no reason for an older woman to take this kind of therapy. Researchers continue to study the effects of estrogen alone.

Medical experts now say women should use hormone replacement therapy only to ease signs of menopause, such as feeling what are called hot flashes. They say women should use it for no more than two years. They note that women can protect their health as they get older with exercise and, if needed, with other drugs.

The maker of Prempro, Wyeth, provided the drug for the study. The company has added the new findings to its product information. But it says the importance to younger women is unclear. Wyeth said it is well known that the risk of dementia increases with age. It says that today most users of hormone therapy are younger, newly menopausal women.

This VOA Special English Health Report was written by Nancy Steinbach.