Division of Epidemiology, Department of Health Sciences Research, College of Medicine, Mayo Clinic, Rochester, MN 55905, USA.
Menopause. 2012 Mar;19(3):272-7. doi: 10.1097/gme.0b013e31822a9937.
The general consensus has been that estrogen is invariably a risk factor for ischemic stroke (IS). We reviewed new observational studies that challenge this simple conclusion.
This was a review of observational studies of the association of premature or early menopause with stroke or IS published in English from 2006 through 2010.
Three cohort studies showed an increased risk of all types of stroke in women who underwent bilateral oophorectomy compared with women who conserved their ovaries before age 50 years. The increased risk of stroke was reduced by hormone therapy in one of the studies, suggesting that estrogen deprivation is involved in the association. Four additional observational studies showed an association of all types of stroke or IS with the early onset of menopause or with a shorter life span of ovarian activity. In three of the seven studies, the association was restricted to IS. Age at menopause was more important than type of menopause (natural vs induced).
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.
普遍认为，雌激素始终是缺血性中风（IS）的一个危险因素。我们回顾了一些新的观察性研究，这些研究对这一简单结论提出了挑战。
这是对 2006 年至 2010 年间以英文发表的关于早发性或早期绝经与中风或 IS 之间关联的观察性研究的综述。
三项队列研究表明，与 50 岁前保留卵巢的女性相比，双侧卵巢切除术的女性发生各种类型中风的风险增加。其中一项研究表明，激素治疗降低了中风的风险，这表明雌激素缺乏与这种关联有关。另外四项观察性研究表明，所有类型的中风或 IS 都与绝经早期或卵巢活动寿命缩短有关。在这七项研究中的三项中，这种关联仅限于 IS。绝经年龄比绝经类型（自然绝经与人工绝经）更为重要。
最近的七项观察性研究的结果对雌激素始终是 IS 的危险因素这一共识提出了挑战，并且可以用一个统一的时间假说来解释。我们假设，雌激素在 50 岁之前对 IS 具有保护作用，而在 50 岁之后或可能在 60 岁之后，它可能成为 IS 的危险因素。这些发现与经历过早发性或早期绝经的女性或考虑在自然绝经前预防性双侧卵巢切除术的女性有关。
