HT increases stroke risk, even in younger women

In postmenopausal women, hormone therapy is associated with a significantly increased risk of stroke regardless of the type of regimen or the timing of therapy initiation, according to a report published in the April 28 issue of the Archives of Internal Medicine.

Francine Grodstein, of Brigham and Women’s Hospital and Harvard Medical School in Boston, and colleagues performed prospective, observational analyses of postmenopausal women enrolled in the 121,700-member Nurses’ Health Study using data from questionnaires mailed biennially to the participants through 2004.

In women currently taking hormone therapy (HT), the researchers found significantly increased risks of stroke for estrogen alone and estrogen plus progestin (relative risks, 1.39 and 1.27, respectively). They observed this increased risk in those who started HT at young ages or near menopause, at older ages, or more than 10 years after menopause. Although short-term use of HT (less than 5 years) started at younger ages was not associated with a clear increase in stroke, the researchers note that this apparently null result was based on a small number of cases. They also found a strong dose-relationship between oral conjugated estrogen and stroke (RR, 0.93 for 0.3 mg, 1.54 for 0.625 mg, and 1.62 for 1.25 mg).

“These findings are virtually identical to those of the Women’s Health Initiative trials. Similar to the Women’s Health Initiative, we did not find any clear difference in the relationship of hormone therapy to stroke for women initiating therapy at younger ages versus at older ages,” the authors write. “In younger women, with lower stroke risk, the attributable risk of stroke owing to hormone use is modest and might be minimized by lower doses and shorter treatment duration.”

Several of the study authors disclose financial relationships with the pharmaceutical industry.

Grodstein F, Manson JE, Stampfer MJ, et al. Postmenopausal hormone therapy and stroke. Role of time since menopause and age at initiation of hormone therapy. Arch Intern Med. 2008;168:861-866.