Two medical studies released on Wednesday provided more damning evidence that giving female hormones to older women does little to improve their health and may in fact harm it.

The studies found that the treatments do not protect women from heart disease, as doctors once believed, and one of the studies found that giving hormones to women actually increases their risk of heart attack.

Both studies appeared in the New England Journal of Medicine, which published a separate piece of research earlier this year suggesting the health risks of estrogen and progestin treatments for older women outweigh the benefits.

In one study in this week's Journal, a research team led by JoAnn Manson of Brigham and Women's Hospital in Boston found that women taking estrogen and progestin increase their risk of a heart attack by 81 percent in the first year.

The study was the final report of a major government look at longterm use of combined estrogenprogestin treatments.

Preliminary findings released last summer showed that women taking the treatment had an increased risk of breast cancer, heart attacks and stroke after five years of use. The study of 16,608 women was ended early once the dangers of hormone treatment became apparent.

Researchers said the latest findings mean that most women who are taking the hormones should stop, and those who have reached menopause should not start.

"Overall, the risk of treatment outweighed the benefits during 5.6 years of treatment," they concluded in their study.

The only remaining reason for prescribing the treatment is to relieve the symptoms of menopause, the Manson team said.

Drugmaker Wyeth, which says its drug Prempro makes up nearly half the market of combined estro-gen-progestin treatments, said the study contained "no new findings" regarding the heart attack data initially published last year.

Wyeth said in a statement that while estrogen-plus-progestin therapy should not be used to prevent cardiovascular disease, it remained a "valuable treatment" for the relief of moderate to severe

menopausal symptoms.

The second study, led by Howard Hodis of the University of Southern California in Los Angeles, found that the arteries of 150 women taking hormone supplements clogged just as rapidly as 76 getting a placebo.

For years, conventional medical wisdom asserted that replacing the estrogen lost after menopause protected against heart disease because the treatment often lowered "bad" cholesterol levels and increased the amount of "good" cholesterol.

That produced a "nearly unshakable belief in the benefits of hormone therapy" in the absence of a real test of the treatment, said David Herrington and Timothy Howard of the Wake Forest University School of Medicine in Winston-Salem, North Carolina.

Even when studies, beginning in 1998, revealed there was no benefit, the belief was so ingrained the findings were heavily criticized and dismissed, Herrington and Howard wrote in an analysis in the Journal.

They said this case illustrates that animal tests and observational studies are no substitute for studies that use placebos and include large numbers of people.