Menopausal women age 50 to 59 years who take standard-dose oral conjugated estrogens have significantly less coronary artery calcification over time than women who take placebo, according to an article in the June 21 issue of the New England Journal of Medicine. The analysis used data acquired through the U.S. Women’s Health Initiative Coronary Artery Calcium Study.

“In the five years since the WHI study ended, new data have emerged that help put the initial findings into perspective. These results showed that in these younger menopausal women, estrogen therapy reduced calcified plaque buildup in the arteries,” said Howard Hodis, MD, Professor of Medicine and Preventive Medicine; Director, Artherosclerosis Research Unit, University of Southern California. “These data support initiation of estrogen therapy, where indicated when a woman first enters menopause and begins experiencing symptoms and bone loss.”

The investigators did not study coronary artery calcification in women who were over 60 years of age at the beginning of the study.

The 1064 women in the WHI study took either 0.625 mg oral conjugated estrogens or placebo for a mean of 7.4 years of treatment, with the follow-up imaging conducted 1.3 years after the trial itself was completed. The mean coronary-artery calcium score after trial completion was significantly lower among women receiving estrogen (83.1) than among those receiving placebo (123.1).

After adjustment for coronary risk factors, the multivariate odds ratios for coronary-artery calcium scores of more than 0, 10 or more, and 100 or more in the group receiving estrogen compared with the group receiving placebo were 0.78, 0.74, and 0.69, respectively.

These findings are consistent with a recent re-analysis of pooled estrogen alone and estrogen plus progestin data from the WHI study, published April 4, 2007, in the Journal of the American Medical Association (JAMA). This study found no apparent increase in coronary heart disease for women who initiated hormone therapy within 10 years of menopause and a statistically significant reduction in total mortality among women aged 50-59 years in the group receiving hormone therapy compared with those in the placebo group.

The authors concluded, “Hormone therapy should not be initiated (or continued) for the express purpose of preventing cardiovascular disease in either younger or older postmenopausal women.”

The authors added, “The current recommendations from many organizations that hormone therapy be limited to the treatment of moderate to severe menopausal symptoms, with the lowest effective dose used for the shortest duration necessary, remain appropriate.”