In older women, higher levels of endogenous oestrogen at baseline predicted a lower risk of heart disease in the Women's Health Initiative trials, a new analysis shows.
"Regardless of treatment, your hormone levels predicted your chance of heart disease," Dr Douglas Bauer, who led the new research at the University of California in San Francisco, told Reuters Health. Bauer and his team presented their findings Sunday at the 93rd annual meeting of the Endocrine Society in Boston.
The WHI trials studied two treatments: oestrogen, and oestrogen plus progestin. The oestrogen-alone trial randomised 10,739 women to take either conjugated equine estrogens, or a placebo, and tracked them for about seven years.
The oestrogen-plus-progestin trial randomised 16,608 women to take either oestrogen plus medroxyprogesterone acetate, or a placebo, and tracked them for more than five years.
Overall, 748 women had heart disease events (e.g., myocardial infarction, silent MI, or cardiac death) during follow-up, includinoestrogenbjects oestrogenstrogen-alone trial and 335 in the oestrogen-plus-progestin trial.
Heart risk decrease with E2 levels
When Bauer and his colleagues analysed baseline quartiles of serum estradiol (E2) levels, they found that heart disease risk decreased with higher E2 levels (p for trend, <0.05).
Furthermore, "baseline levels of total E2 did not modify the relationship between treatment and coronary heart disease risk" inoestrogentrial, thoestrogenchers said in their abstract for their meeting.
In the oestrogen-plus-progestin trial, women in the highest quartile of E2 levels had a 70% lower risk of heart disease compared to those in the lowest quartile (hazard ratio: 0.3). In the oestrogen-alone trial, women with the highest E2 levels were 50% less likely to suffer a cardiac event compared to those with the lowest E2 levels (HR: 0.5).
"This is more likely to be useful in women trying to predict their risk of heart disease thaoestrogening to determine the best treatment," Bauer said. "In the future, you could, perhaps, measure oestrogen to tell the likelihood of heart disease." - (Rob Goodier/Reuters Health, June 2011)
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