NEW YORK (Reuters Health) - Contrary to some earlier reports, a new study suggests that hormone replacement therapy does not slow the progression of atherosclerosis--a build-up of fatty plaque in the arteries--in postmenopausal women. The study is the first to compare women randomly assigned to take hormones or no hormones, the ``gold standard'' of clinical trials.

Previous studies found that women who took hormones after menopause had a 30% to 35% lower risk of heart disease compared with women who did not. However, it was not clear if the hormones were the reason, or some other factor--such as a healthier lifestyle in general among hormone-users--was responsible.

In the new study, Dr. Peter Angerer and associates from Klinikum der Universitat Muenchen-Innenstadt in Muenchen, Germany looked at women who already had mild atherosclerosis, but no symptoms of heart disease.

The investigators measured the amount of narrowing in the carotid artery--the large artery in the neck--in 264 women before and after either a year of treatment with hormone replacement therapy (HRT) or no hormones at all.

The thickness of the carotid artery wall--an indication of the degree of atherosclerosis--increased slightly during the course of the year in women who took hormones and in women who did not take them, and there was no difference between the two groups in terms of the amount of increase.

Hormone replacement therapy did decrease LDL (''bad'') cholesterol, the authors report in the February issue of Arteriosclerosis, Thrombosis and Vascular Biology: Journal of the American Heart Association

Women taking hormone replacement therapy experienced more breast tenderness and spotting than did women not taking the drugs, the researchers note, but side effects were otherwise similar in the groups.

Angerer and associates conclude that one year of hormone replacement therapy does not slow the progression of atherosclerosis in postmenopausal women who already face an increased risk of heart disease and stroke by virtue of their slightly blocked arteries.

These results do conflict with the report last year that indicated a reduction in the risk of atherosclerosis in women who decided to take hormone replacement therapy for menopausal symptoms.

``Unfortunately, we're seeing a lot of studies that each looked at tiny parts of the whole picture,'' Dr. Nieca Goldberg, a spokesperson for the American Heart Association, told Reuters Health. ``The results can be confusing for everyone.''

Goldberg said, ``The decision to use HRT should be based on the wish to control menopausal symptoms, rather than to prevent heart disease or atherosclerosis or stroke.''

Goldberg, of Lenox Hill Hospital in New York, added, ``Women would be better served by getting adequate treatments for other risk factors--high blood pressure, high cholesterol, and so on--and by changing their lifestyles, (for example) exercising more, giving up smoking, eating less fat. It may be some time before research results allow us to develop a comprehensive HRT plan for everything.''

SOURCE: Arteriosclerosis, Thrombosis, and Vascular Biology 2001;21:262-