HRT Increases Stroke Risk

By Steven Reinberg
HealthDay Reporter
Tuesday, April 29, 2008; 4:00 AM

Copyright © 2008 ScoutNews, LLC. All rights reserved.

MONDAY, April 28 (HealthDay News) -- No matter when postmenopausal women start hormone replacement therapy (HRT), high doses of the treatment increase their risk of stroke, a new study finds.

The risk for stroke does appear lower in younger women taking HRT and in those taking the lowest doses of estrogen, Harvard researchers say. However, in women who took high doses of hormones, that increased risk was as much as 62 percent.

"If you take medium to higher doses of hormone therapy, you are at increased risk of stroke," said Dr. James Liu, chairman of the Department of Obstetrics and Gynecology at MacDonald Women's Hospital, University Hospitals Case Medical Center in Cleveland.

"If you are on estrogen, the risks of clotting abnormalities are slightly increased versus if you are not on estrogen," Liu said. "So, the risk of stroke is increased."

The report was published in the April 28 edition of the Archives of Internal Medicine.

In the study, Francine Grodstein and colleagues at Brigham and Women's Hospital and Harvard Medical School collected data on 121,700 women who participated in the Nurses' Health Study from 1976 to 2004.

The researchers looked at the association between HRT and stroke. Over the course of the study, 360 women who had never used HRT had strokes compared with 414 women taking hormones, Grodstein's team found.

"This increased risk was observed for women initiating hormone therapy at young ages or near menopause and at older ages or more than 10 years after menopause," the researchers wrote.

However, women taking HRT for less than five years at younger ages did not have a clear increase of stroke, which might be due to the small number of cases studied, the researchers noted.

"The incidence of stroke was relatively low in younger women, and the attributable risk in women aged 50 through 54 years indicated approximately an additional two cases of stroke per 10,000 women per year taking hormones," the researchers added.

Liu noted that older women are at an increased risk of stroke due to their age, whether or not they are taking HRT.