Eighteen years ago this month the National Institutes of Health (NIH) announced that it would sponsor a landmark study to examine women and cardiovascular disease. Known as the Women's Health Initiative (WHI), the study enrolled more than 161,000 women. By 2004 however, the government had ended two arms of the study involving estrogen after researchers found it posed a small but detrimental risk for stroke to postmenopausal women taking the hormone. The findings caught many members of the scientific community by surprise as estrogen had previously been shown to protect the brain from stroke in animal models. Stroke, also known as a brain attack, is America's third leading cause of death. It typically occurs when blood flow to the brain is blocked, usually due to a clogged artery. When a stroke occurs, brain damage can result, especially in the area known as the hippocampus, thought to be the site for memory, memory loss, and learning. Despite the possible link between estrogen and stroke many women continue to take the hormone to manage their menopausal symptoms.
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