Years after a large study on hormone replacement therapy revealed health risks among older women using it to prevent chronic disease, the number of women who take hormones continues to decline, according to a new study.

The researchers found that in 2009 and 2010, less than five percent of women over age 40, who had already gone through menopause, use either estrogen alone or estrogen and progestin. That compared to about 22 percent in 1999 and 2000.

Dr. JoAnn Manson, a leader of the Women's Health Initiative (WHI) research and a professor at Harvard Medical School, said it was appropriate that there was a decline in the number of women using hormones.

The WHI reported in 2002 that taking estrogen plus progestin appeared to increase the risks of stroke, heart disease and breast cancer.

"We now understand that women more distant from the onset menopause and at increased risk of cardiovascular disease have adverse outcomes on hormone therapy and that hormone therapy should not be used for prevention of heart disease or prevention of chronic disease because it is associated with some risks," Manson, chief of preventive medicine at Brigham and Women's Hospital, told Reuters Health.

The latest report, which included survey responses from more than 10,000 women, shows a steady drop and supports the results from other studies assessing the short-term impacts of the WHI.

Brian Sprague, the lead author of the current study and a professor at the University of Vermont, and his colleagues found that as the years progressed, fewer and fewer women reported taking hormones.

"From this study we have no way of teasing out what's driving these changes," Sprague said, adding that it's likely due to concerns from both women and their physicians about the health risks of taking hormones.

An overreaction?

The increased breast cancer risk from hormone therapy was a major driver in turning people away from hormone therapy, said Dr. Robert Langer, a research member of the WHI and currently the principal investigator at the Jackson Hole Center for Preventive Medicine in Jackson, Wyoming.

"I think it's a really substantial overreaction" to the harms that were found in the Women's Health Initiative (WHI) study, Langer told Reuters Health.

The WHI found that eight additional women out of every 10,000 would get breast cancer, an increased risk of 26 percent.

But he said those results applied to older women taking hormones to prevent chronic disease, not necessarily to younger women seeking relief from menopausal symptoms.

"The pendulum may have swung too far in the direction away from hormone therapy use," Manson said.

Hormones are considered the most effective treatment for moderate and severe symptoms of menopause, such as hot flashes and night sweats.

For those women who use hormones, the U.S. Food and Drug Administration recommends they be at the lowest dose and for the shortest amount of time.

Manson said it's possible that concerns over the health risks of hormone therapy may be preventing women from getting relief from symptoms.

"In a younger woman who has hot flashes, night sweats, and impaired quality of life, it is very likely that the benefits of short term hormone therapy will outweigh the risks," she said.

She advises any woman seeking relief for menopause symptoms to discuss her individual risks and benefits of hormone therapy with a doctor.

After the initial findings in 2002, subsequent studies - both from WHI data and other trials - have tried to clarify the health risks of hormone therapy for different age groups.

For younger women closer to menopause, for instance, some studies have found an increased risk of breast cancer while others have found a lower risk of heart disease and death compared to women not taking hormones.

Manson is part of an ongoing trial looking at the effects of hormone therapy on heart disease risk for women ages 42 to 58 - a younger age group on average than the WHI.

Another ongoing study is comparing the heart disease risks among women who begin taking hormone therapy soon after menopause or more than a decade later.