Hormone Therapy Can Cut Women’s Heart Disease Risk : Health: Study shows up to 25% drop, depending on post-menopause regimen. Tailored treatment is seen as key.
Post-menopausal women can significantly lower their risk of heart disease by taking hormone therapy, according to a highly anticipated study released Thursday at the American Heart Assn. meeting in Dallas.
The Post-Menopausal Estrogen/Progestin Interventions (PEPI) study is the first to monitor how various hormone regimens affect key cardiovascular risk factors. The results should help women and their doctors better determine the risks and benefits of hormone replacement therapy, which has long been a complicated and widely debated issue.
The three-year study of 875 healthy women showed that those taking any one of four hormone regimens experienced an increase in high-density lipoprotein (HDL) or good cholesterol--which reduced their risk of heart disease by 12% to 25%, depending on which regimen they followed.
All four treatments also caused a drop in low-density lipoprotein (LDL), or bad cholesterol, compared to a placebo group. Hormone therapy also triggered a decrease in fibrinogen, a blood-clotting factor that usually increases with age and is strongly associated with strokes and heart attacks. There was no effect on blood pressure.
The hormone did not increase the risk of breast cancer, as some had suggested it might, although experts say the study did not last long enough to draw any definitive conclusions about this risk.
“The results of this landmark study provide the best available guide for post-menopausal women and their physicians as they seek safe hormonal regimens that will improve their heart disease risk factors,” said Dr. Claude Lenfant, director of the National Heart, Lung and Blood Institute, which sponsored the study at seven research centers throughout the country, including UC San Diego and UCLA.
Natural sex hormones apparently help protect women against heart disease before age 50. But after menopause, when hormone production ceases, the rate of heart disease in women climbs quickly and eventually equals the rate in men. Heart disease is the leading cause of death in American women.
Earlier studies of women who had experienced heart attacks and those who had not found that those taking hormones had up to 50% lower risk. The new study was the first to measure heart disease risk factors in a large group of women from the time they started hormone therapy. “The PEPI results are a significant step forward in our understanding of hormonal therapy and its effects on HDL cholesterol, fibrinogen and other factors which affect a woman’s risk of heart disease,” Lenfant said.
The women, ages 45 to 64, were randomly assigned to one of five groups: a placebo, daily estrogen alone, daily estrogen plus a daily synthetic progestin, daily estrogen plus a synthetic progestin taken 12 days per month or daily estrogen combined with natural progesterone taken 12 days a month.
The results indicated that hormone therapy, when tailored to the individual, can indeed protect against heart disease without boosting the risk of cancer or other problems.
Previous studies have shown that estrogen alone promotes the growth of uterine tissue, called the endometrium, which can lead to cancer. But when progestin is added to the regimen, the risk of endometrial cancer vanishes, so physicians typically prescribe progestin for part of the month.
But other studies have indicated that progestin may erase part or all of the cardiovascular benefits of estrogen and may also increase the risk of breast cancer.
“No one knew how much progestin would diminish the protective effect,” said Suzanne Oparil, president of the American Heart Assn. “Some studies showed it would completely diminish the positive effect, others not at all. (PEPI) shows the truth is somewhat in between.”
Women taking estrogen alone or the combination of estrogen and natural progesterone--a new form called micronized progesterone--had the most favorable cholesterol benefits.
However, PEPI also showed that women who have not had a hysterectomy--surgery to remove the uterus--probably should not take estrogen alone. One-third of the women on estrogen alone experienced severe precancerous endometrial changes and had to drop out of the study.
“These results provide the strongest evidence to date that estrogen alone produces the best effect on HDL cholesterol. However, the high rate of potentially harmful endometrial changes makes combination hormone therapy advisable for most women with a uterus,” said Dr. Elizabeth Barrett-Connor, a UC San Diego researcher who helped direct the trial.
Women with a uterus who opt for estrogen alone should undergo regular biopsies to detect cancer, she said.
“The recommended regimen would be: If you have a uterus, estrogen plus some progesterone; natural progesterone appears to be better. For women without a uterus, estrogen (alone),” Oparil said.
In another positive finding, test subjects showed no increased risk of breast cancer. Previous studies have indicated a possible link between breast cancer and hormones. But the study is too short for the breast cancer finding to carry much significance, Oparil said.
“We need long-term follow-up to determine the breast cancer risk,” she said.
The women were also studied for the effects of hormones on osteoporosis, but those findings were not released Thursday.
Longer studies, such as the 15-year Women’s Health Initiative, will provide a more definitive picture of all the risks and benefits of hormones, Lenfant said.
“We must wait for the results of large clinical trials such as the Women’s Health Initiative to determine whether increasing HDL ultimately reduces a woman’s chance of developing or dying from heart disease,” he said.
