Premature menopause or early menopause and risk of ischemic stroke

The findings from seven recent observational studies challenge the consensus that estrogen is invariably a risk factor for IS and can be reconciled by a unifying timing hypothesis. We hypothesize that estrogen is protective for IS before age 50 years and may become a risk factor for IS after age 50 years or, possibly, after age 60 years. These findings are relevant to women who experienced premature or early menopause or to women considering prophylactic bilateral oophorectomy before the onset of natural menopause.