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Postmenopausal oestrogen therapy when started under age 60 reduces coronary artery narrowing

Mediacom

Saturday 23 June 2007, 9:00AM

By Mediacom

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Coronary Heart Disease is the most common cause of death and illness in Western Women. In 2002 The US Women's Health Initiative, the first long-term randomised placebo controlled trial of HRT, reported that, contrary to previous observational studies and expectations, an increase in heart disease was seen when its relatively elderly population was treated with HRT. The women in WHI started HRT at an average age of 63 and 13 years after menopause.


A new analysis from this same trial was reported this week in the New England Medical Journal (Manson et al, Estrogen Therapy and Coronary-Artery Calcification NEMJ 2007;356:2591-602) shows that the women in their study, who commenced oestrogen therapy nearer menopause and under age 60, had a 35% reduction in their coronary artery plaque burden. The study measured coronary artery plaque and calcification which is a strong marker for coronary artery narrowing and the future risk of heart attack. When the results were analysed by those who had more than an 80% adherence to taking their oestrogen there was a 59% reduction in plaque.


This important report supports other recent clinical studies suggesting that there is a critical window of therapeutic opportunity to prevent heart disease in women around and for some years after menopause. The vast majority of women who use HRT take this therapy around menopause to alleviate menopausal symptoms and therefore may also be reducing their chance of heart disease. The study needs to be repeated for those who took oestrogen combined with progestogen. Progestogen is added in women with a uterus to prevent uterine bleeding and uterine cancer. In WHI, only the combined HRT regimen was associated with an increase in breast cancer and this increased after 7 years of therapy in those who had not used HRT before the trial. This increase was 8/10,000 women years or less than 0.1% per year of use. If the reduction of coronary artery plaque does translate into a large reduction in heart disease then the risks and benefits of postmenopausal oestrogen therapy need to be reappraised. Such a reappraisal was published this week in the Medical Journal of Australia (MacLennan AH. HRT: A reappraisal of the risks and Benefits. MJA 2007; 186:643-6).


"The key to understanding HRT and maximising its benefits is to use it when indicated from near menopause" said Dr Bev Lawton, President of the Australasian Menopause Society.


"However, oestrogen will not unblock arteries once they are narrowed by plaque in later post menopausal years. More long-term research is necessary but this study is good news for many women who feared taking oestrogen near menopause because of a purported risk to their heart. This risk seems only to affect much older women starting HRT too late. For women starting oestrogen therapy near menopause there appears a major benefit."