A 2002 study that led millions of women to throw out their hormone pills may have overestimated the dangers of that medication to women in their 50s, new research suggests.
The new study in Wednesday's Journal of the American Medical Association found that for women near the start of menopause, the pills do not increase the incidence of heart attacks or other cardiac complications.
Findings regarding stroke were less clear cut, but researchers said that the youngest women appeared to be at the lowest risk.
Women do have a heightened risk of heart attacks and strokes when they begin taking the pills in their 60s and 70s, the study said. Research also has shown that hormone therapy increases the likelihood of breast cancer, with the danger increasing the longer the pills are used.
The new report supports current medical practice: giving women the pills only for a few years, to relieve hot flashes, night sweats and other symptoms of menopause.
"This study shows that women who are very close to their menopause, in their early 50s, probably don't have to worry too much about a heart attack. But they can't get away from that risk of a stroke or that risk of breast cancer," said Cynthia Pearson, executive director of the National Women's Health Network, an advocacy group not involved with the study.
Through much of the 1980s and '90s, hormones rode an unparalleled crest of popularity, said to be a fountain of youth for aging women, with the power to smooth skin, boost energy and reduce the risk of heart attacks and mental impairment. At one point, they became the hottest-selling drugs in the country.
But it turned out that many of the claims about hormones were not based on gold-standard scientific evidence. Eventually, top federal scientists concluded that the rush to put hormones into the hands of every woman older than 50 was a reckless pursuit based on insufficient science. That led to a landmark study called the Women's Health Initiative.
The first wave of results from that hormone study landed with a jolt in the summer of 2002, challenging the common strategy of placing women on the drugs to prevent heart disease. ''We know now that practice was misguided," said Dr. JoAnn E. Manson, an author of the study and chief of preventive medicine at Brigham and Women's Hospital in Boston.
The report generated considerable controversy - and an equally considerable plunge in the sale of hormones. Wyeth Pharmaceuticals, a major maker of hormones, reported that hormone sales in 2006 were 44 percent lower than in 2002.
Some specialists said this week that the 2002 study overstated the risks of hormone therapy, especially to healthy, younger women.
"It took the pendulum a little too far to the risk side of hormones," said Dr. Isaac Schiff, a Massachusetts General Hospital gynecologist who led a committee that reviewed hormone therapy for the American College of Obstetricians and Gynecologists.
Some specialists were especially critical of the 2002 study for including so many older women - the average age of participants was 63 - when women typically enter menopause at 51. In those first years of menopause, women routinely experience the worst symptoms.
The latest study pooled data from the 2002 study and another related report, allowing for more precise interpretation of how the drugs affected women in different age groups.
Overall, the study found that women taking hormones between the ages of 50 and 59 were less likely to die during the five-year study period than women not taking the medicine.
In an interview this week, Dr. Jacques E. Rossouw, a leader of the Women's Health Initiative study, said that scientists in 2002 were determined to alert women and their doctors to the potential heart risks imposed by hormones.
"Our media effort and our scientific effort were pretty clear-cut and the conclusions we drew were pretty clear-cut: don't use hormones for prevention of coronary heart disease," said Rossouw, a specialist at the National Heart, Lung, and Blood Institute and an author of Wednesday's study.
The new study does not address the health implications of women beginning hormone therapy in their 50s and continuing it for decades.
Such a study, Rossouw said, would be impossible to conduct because of the cost and difficulty persuading enough women to take the pills for long enough to reach scientific conclusions.