Oestrogen Therapy and Coronary Artery Calcification

Women aged 50-59 who took oestrogen show a reduced risk of coronary plaque build up.

A new study from the Women’s Health Initiative (WHI) has evaluated, for the first time in a randomized trial, the relationship between oestrogen therapy and coronary artery calcium in young postmenopausal women. JoAnn Manson, MD, from Brigham and Women’s Hospital (BWH) and colleagues found that oestrogen therapy in women aged 50-59 is related to lower coronary artery calcium, a marker for plaque blockage in the coronary arteries and a predictor of future risk of heart attack. These findings are published in the June 21, 2007 issue of the New England Journal of Medicine. “These findings lend further support to the theory that oestrogen may slow early stages of plaque build up and lead to less hardening of the arteries supplying blood flow to the heart,” said Manson, lead author of the study and chief of Preventive Medicine at BWH. “These results, together with previous WHI findings about lower rates of coronary bypass surgery and angioplasty for younger women who take oestrogen, provide reassurance for recently menopausal women who are considering oestrogen therapy for the short-term treatment of menopausal symptoms,” added Manson, who is also one of the principal investigators of the WHI. Coronary artery calcium was measured by cardiac computed tomography (CT scans) in 1064 women who were aged 50-59 years and randomly assigned to oestrogen-alone therapy (conjugated equine estrogens, 0.625 mg/d) or to placebo at the start of the WHI trial. After an average of 7.4 years of treatment, the women receiving oestrogen were 30-40% less likely to have severe coronary artery calcium than women receiving placebo. Among women who were taking their study medications regularly, women receiving oestrogen had a 60% lower risk of severe coronary calcium. These risk reductions were statistically significant.The authors caution, however, that the new study should not be interpreted to mean that women should take oestrogen to protect their hearts and stress that more research is needed to evaluate the effects of oestrogen in younger women. “Although these findings indicate that oestrogen therapy in younger menopausal women is related to less plaque in the arteries supplying the heart, this does not mean that oestrogen should be taken for the express purpose of preventing cardiovascular disease,” concluded Manson, who is also a professor of medicine at Harvard Medical School and author of Hot Flashes, Hormones & Your Health. “Oestrogen is known to have other risks and should be used only for the treatment of menopausal symptoms at the lowest dose for the shortest duration necessary,” she added. This research was funded by the National Heart, Lung and Blood Institute. Pills were provided by Wyeth, which had no other role in the study. The effect of oestrogen on the development of atherosclerosis in recently menopausal women is also being studied in the Kronos Early Oestrogen Prevention Study (KEEPS). The KEEPS trial is comparing low doses of oral versus transdermal (patch) oestrogen in the prevention of blood vessel narrowing.(Source: Brigham and Women’s Hospital : July 2007)