Researchers say hormone-replacement therapy may still be a valuable option for some younger women.
If given to women at age 51 instead of age 63 or older, hormones might offer protection from heart attacks, stroke and other conditions.
One new study, called "Kronos Early Estrogen Prevention Study," has begun recruiting newly menopausal women at eight U.S. medical centers. The privately funded study will place 720 women on one of three treatment regimens: oral estrogen, estrogen via a skin patch or a placebo.
All of the women taking estrogen will receive progesterone, which is given in combination with estrogen to prevent overgrowth of the uterine lining and possible uterine cancer.
Investigators will take periodic scans of the carotid and coronary arteries to measure the effects of hormone therapy on the development and progression of heart disease.