Higher Levels of Estrogen Prove to Lead to Higher Incidence of Stroke

Predictions from doctors and researchers said that higher levels of natural estrogen leads to a higher risk of stroke. In February of 2006, a new finding suggests that there may be a new way to prevent this deadly disease.

More studies need to be done in order to confirm these results, but these findings support the information that is already known about hormones, several experts expressed who were not connected with the new work.

"This is really interesting," said Dr. JoAnn Manson, a women's health researcher and chief of preventive medicine at Harvard-affiliated Brigham and Women's Hospital in

Boston."These findings would be consistent with the increased risk of stroke seen in the Women's Health Initiative," the landmark federal study that prompted many women to stop taking estrogen pills after menopause, she said.

The new research was led by Dr. Jennifer Lee of University of California in San Francisco and presented Friday at an American Stroke Association conference.

It involved 7,290 women who participated in a recent study of raloxifene, a "designer estrogen" that blocks that hormone's action in some parts of the body, like the breast, while increasing its effects in others, like bones.

The study's main goal was testing raloxifene for treating the bone-thinning disease osteoporosis, a use for which the drug ultimately won approval. Women with osteoporosis who were at least two years past menopause were randomly assigned to get raloxifene or dummy pills for four years.

Estradiol dramatically drops after menopause, and half of the 2,447 women given the dummy pills had no detectable levels of it. Among the rest, those with lower estradiol levels had a 70 percent lower risk of stroke than those with higher levels, she found.

"To see this effect in such a large population ... is quite striking and is surprising," Lee said.