(RxWiki News) Naturally occurring estrogen may aid with ischemic stroke prevention for women under the age of 50. However, in older women the sex hormone may instead increase the risk of stroke.
Previous research had suggested that estrogen is a stroke risk factor at any age, though the new research suggests it is not a risk factor until the age of 50, or possibly 60.
"Consider hormone replacement after early menopause."
Dr. Walter Rocca, study author and an epidemiologist and neurologist at Mayo Clinic, said he was surprised because the results were unexpected. He said the old idea that estrogen is always a problem in the brain has to be corrected. Though it may be a problem in older women, in younger women, it may be important in protecting the brain from strokes.
Researchers reviewed seven published articles that studied the association of premature or early menopause with stroke risk. One of those studies was a previous Mayo Clinic study.
After reviewing the results, they concluded that estrogen may protect from stroke before the age of 50, an age that is typical of when women go through menopause.
In one study that was reviewed, the increased stroke risk was reduced through hormone therapy, suggesting that estrogen deprivation may be involved in the association. Four other observational studies demonstrated an association for all types of strokes with the early onset of menopause. In three of those studies, the link was restricted to ischemic strokes.
Dr. Rocca said the finding could mean that women who experience early menopause, defined as before the age of 45, should consider taking estrogen through the age of 50 to help prevent strokes. This includes women who began menopause naturally, or as a result of ovary removal.
The review study was published in the journal Menopause.