"We will never know when we should stop hormones," said Dr. Michelle Warren of the Columbia University College of Physicians and Surgeons, who spoke at the news conference and urged the shortest use possible. But "if you have been on the hormone since the time of menopause, I am not worried anymore."

The results were "clear and striking," wrote Dr. Michael E. Mendelsohn and Dr. Richard H. Karas of the Tufts University School of Medicine in an editorial accompanying the study. "Now, some clarity about hormone replacement therapy and heart disease is emerging."

The newest findings probably will not drastically change clinical practices, said Dr. Robert Greenfield, a cardiologist at Orange Coast Memorial Medical Center in Fountain Valley. "Women who are thinking about taking them should do so because they have peri- menopausal symptoms," and not to prevent heart disease, he said. "Using them in modest doses for symptoms is the way to go."