TUESDAY, Jan. 24, 2006 (HealthDay News) -- While controversy on the safety of hormone replacement therapy (HRT) continues, a new study suggests that when a woman begins the therapy may be key to whether or not it will protect her from heart disease.
According to the new report, women who start HRT when they are younger, near the onset of menopause, have about a 30 percent lower risk of coronary heart disease compared with women who never use hormones. However, women who start HRT 10 years or more after menopause, or after the age of 60, gain no cardiovascular benefit from the therapy.
"The timing of hormone therapy in relation to age and time since menopause may be a key factor in whether these hormones protect the heart or increase risk of heart disease," said researcher Dr. JoAnn E. Manson, the chief of the division of preventive medicine at Brigham and Women's Hospital, in Boston.
These findings may help to address the discrepancies in results from earlier studies, Manson said.
The report appears in the January/February issue of the Journal of Women's Health.
In their study, Manson and her colleagues looked at the association between heart disease and HRT as they relate to age. The women in the study had all participated in the Nurses' Health Study from 1976 to 2000.
The team found that women who started HRT near menopause had a significantly reduced risk of heart disease compared with women who didn't start HRT. In contrast, women who started HRT after age 60 or 10 or more years after menopause gained no protective effect from hormone replacement.
"What we need is a way to identify women who are good candidates for HRT versus women who are poor candidates for HRT," Manson said. "The findings that age and time since menopause may be key factors is an important first step."
A lot of women who are good candidates for HRT may have been scared away by findings suggesting no heart benefit or that the risk of heart disease might outweigh the benefits, Manson said. "The risk of heart disease and stroke are lower in the younger, recently menopausal women," she said.
But in older women, existing damage to vessels may be the reason HRT does not protect them from heart disease. "If a blood vessel already has advanced atherosclerosis, hormone therapy may be more likely to cause a clot," Manson speculated.
"However, if the blood vessel is open, the increase in clotting risk usually will not translate into a heart event, and some of the benefits may predominate as improvement in cholesterol, improvement in insulin sensitivity and antioxidant effects. Estrogen may actually delay the development of artherosclerosis in those women," she added.
One expert doesn't think the findings should change current recommendations.
"This is an important question," said Dr. Nieca Goldberg, the chief of women's cardiac care at Lenox Hill Hospital, in New York City. "However, we would need a randomized trial. The results of this study are not going to change the current guidelines on the prescription of hormone therapy," she said.
Goldberg believes that women who want to lower their risk of heart disease should stick to reducing the known risk factors.
"Women should continue to use proven therapy," she said, noting that lifestyle changes, such healthy diets and exercise, "clearly have been proven to reduce risk." Of course, "that may not be as easy as taking a pill," Goldberg added.
In addition, women who need treatment for risk factors like high blood pressure and high cholesterol should be taking medications that have been documented to reduce the risk of heart attack and stroke in women, Goldberg said. "We still do not prescribe HRT for heart disease prevention."
Concerns about HRT were initially raised by the Women's Health Initiative, a landmark study involving 27,000 participants that caused many women to discontinue their use of hormone therapy.
Researchers halted the WHI study in 2002 after they found the regimen entailed more health risks -- most notably an increased risk for breast cancer and stroke -- than benefits.
Several subsequent studies have also questioned the WHI findings. One study noted some women in the WHI project were in their 60s and 70s who hadn't been on hormones before. Because these women were older, they were already at greater risk of cardiovascular problems, researchers reasoned.
More information
For more on HRT, head to the National Institutes of Health.
