More bad news for hormone therapy users …

Stroke risk nearly doubles with use of combined hormone therapy

In what many natural health advocates hope will be the “death blow” to artificial hormone replacement therapy, a Women's Health Initiative (WHI) research program has found that healthy older women who take estrogen and progestin combined, the most common form of hormone replacement therapy, have a higher risk of  suffering a stroke.

In recent months, HRT has been implicated in a number of health problems, including an increased risk of dementia. In this study, the authors concluded that the risks associated with combined hormone therapy outweigh its potential benefits. Their report was published in the May 28 issue of the Journal of the American Medical Association.

The study of 16,608 postmenopausal women between the ages of 50 and 79 suggests that those taking estrogen plus progestin had an overall 31% higher risk of stroke than women taking a placebo. Of those studied, 151 patients taking hormones had strokes, compared with 107 in the placebo group.

Almost 80% of strokes were ischemic, which are characterized by blockage of a cerebral artery. The hormone therapy group had a 44% increased risk for ischemic stroke compared to those taking placebo. The risk for hemorrhagic stroke, characterized by bleeding in the brain, did not significantly differ among the two groups studied.

"Though the women in the trial exhibited a variety of other risk factors for stroke, which we took into account and which affected the onset of increased risk, the adverse effects of estrogen plus progestin were demonstrated across the diverse population studied," said Dr. W. Jerry Mysiw, a physical medicine and rehabilitation specialist at The Ohio State University Medical Center and a co-author of the study.

Among the risk factors that researchers determined did not modify the effects of estrogen plus progestin on stroke risk were age, smoking, high blood pressure, diabetes, history of cardiovascular disease and lower use of vitamin C supplements.

Women in the estrogen plus progestin part of the WHI program stopped taking their study pills in July after research results indicated that for those on the combined therapy, the overall risks (breast cancer, heart attacks, stroke and blood clots) outweighed the benefits (fewer fractures and colorectal cancers). This report expands on those initial findings by examining subtypes of stroke and providing additional data on the effects of the combined hormone therapy in various subgroups of women.

"Defining exactly what could be considered safe short-term use is problematic," Dr. Mysiw said. "What we do know is the excess risk for stroke became apparent by the second year of combined hormone use."

The women in the study were followed for an average of 5.6 years at the WHI's 40 clinical centers in the United States, including OSU Medical Center, where Mysiw is part of the team of Women's Health Initiative investigators.