补充维生素E，降低中风风险

Vitamin E Supplements Affect Stroke Risk
Vitamin E Supplements Increase Risk for Hemorrhagic Stroke but Decrease Risk for Ischemic Stroke, Researchers Say
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* `) ^! B: N, j9 ~, P6 ]( @WebMD Health NewsReviewed by Laura J. Martin, MD Nov. 5, 2010 -- Although the risk remains relatively small, researchers have found that taking vitamin E supplements increases the risk of hemorrhagic stroke, in which bleeding occurs in the brain. But vitamin E supplements reduce the risk of ischemic stroke, the more common type of stroke, in which blood flow to the brain is blocked, the researchers say.
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0 t& p, t  G7 ~9 v" [Markus Schürks, MD, a researcher at Brigham and Women’s Hospital in Boston, led an international team that analyzed data from the medical literature. The group reviewed nine trials published through January 2010 that included more than 118,000 study participants; 59,357 took vitamin E supplements and 59,408 took a placebo. The trials did not include people who took multivitamins.

A Visual Guide to Understanding Stroke
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Mixed Results on Vitamin E
Vitamin E did not significantly affect the risk of stroke overall. The study did not evaluate which doses of vitamin E produced which outcomes. Instead, it looked at any association between vitamin E use and stroke. When looking at different types of stroke, researchers found that:

1 I  F9 N. a# w/ WTaking vitamin E supplements increased the risk of hemorrhagic stroke by 22% but reduced the risk of ischemic stroke by 10%.
- m0 E9 ?5 k9 y% e- yA total of 223 hemorrhagic strokes occurred among 50,334 who took vitamin E supplements, whereas 183 hemorrhagic strokes occurred among those taking a placebo.
4 |" ~2 q8 S( V- A: A; G! NA total of 884 ischemic strokes occurred among 45,670 people taking vitamin E supplements, whereas 983 ischemic strokes occurred among 45,733 people taking a placebo.
The authors estimate that based on this data, there could be one additional hemorrhagic stroke for every 1,250 people taking vitamin E, whereas one ischemic stroke would be prevented per every 476 people taking vitamin E.
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The findings are published in today’s online edition of BMJ.
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% H/ D$ q  v! a1 d3 Q- b“Given the relatively small risk reduction of ischemic stroke and the generally more severe outcome of hemorrhagic stroke, indiscriminate widespread use of vitamin E should be cautioned against,” the authors write.

Previous studies had suggested vitamin E supplements may reduce cardiovascular disease, but other studies have indicated that taking high doses of vitamin E might increase the risk of death. An estimated 12.7% of the U.S. population takes vitamin E supplements, according to the report.

Stroke is the third leading cause of death in the U.S., after heart disease and cancer, according to the American Heart Association. Stroke kills more than 137,000 people every year in the U.S. and accounts for one out of every 18 deaths. Sixty percent of stroke deaths occur among women.

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维生素E添加剂影响中风的风险
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研究人员说，维生素E添加剂增加出血性中风的风险，但是降低缺血性中风的风险
Katrina Woznicki报道
2010年11月5日健康新闻（由Laura J. Martin医学博士审阅）---尽管风险仍是相对小的，但是研究人员已经发现服用维生素E添加剂增加出血性中风的风险，其中大脑中出现出血。

; o3 }1 @& H4 L, u3 B但是维生素E添加剂降低最常见中风的类型--缺血性中风的风险，其中大脑的血流被阻塞，研究人员说。
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布莱罕和波士顿妇女医院研究员Markus Schürks医学博士领导着一个国际性团队，他们分析了来自医学文献的数据。这个团队回顾了至2010年1月发表的9个试验，其中包括了118000名研究参加者；59357人服用维生素E添加剂，59408人服用安慰剂。这些试验们不包括服用多种维生素的人们。
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) _  e9 x0 `3 q* p9 [理解中风的图片
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7 [* T# _! j) Y, m1 {7 R" Q2 W维生素E的混合结果
* z! t2 u4 F) B# d, f# ~9 c4 I' _4 n维生素E不显著影响中风的总体风险。这项研究没有评估哪种剂量的维生素E产生哪种结果。它反而观察了服用维生素E和中风之间的任何联系。

当观察不同类型的中风时，研究人员发现：
服用维生素E添加剂增加22%的出血性中风的风险，但是降低10%的缺血性中风的风险。
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9 M5 [! w& h+ Y8 F7 e5 m0 _& o: W& t在50334名服用维生素E添加剂的人中，总计有223人出现出血性中风，而在服用安慰剂的人中有183人出现出血性中风。
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在45670名服用维生素E添加剂的人中，总计有884人出现缺血性中风，而在45733名服用安慰剂的人中有983人出现缺血性中风。

& c6 D9 Y" S" w' n$ f作者们估计，根据这些数据，每1250名服用维生素E的人中就有一例额外的出血性中风，而每476名服用维生素E的人中就能预防一例缺血性中风。

2 X7 I" X2 K& S6 A9 E5 n/ M这些发现出版在今天的《英国医学杂志》网络版上。
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. ?" r; N5 [4 B. k6 Q9 v& @" F1 [* h“考虑到相对小的降低缺血性中风的风险和通常较严重的出血性中风的结果，随意的广泛使用维生素E应该被谨慎地反对，”作者们写道。

0 P. q" b6 ^" M2 n以前的研究已经提示维生素E添加剂可能减少心血管疾病，但是其它的研究已经指出服用大剂量的维生素E可能增加死亡风险。根据这个报告，估计12.7%的美国人服用维生素E添加剂。

2 p0 Q3 e' K3 h: ]根据美国心脏病学会，中风是美国继心脏病和癌症之后的第三位的主要死亡原因。在美国，中风每年杀死超过137000人，并且占死亡的1/18。女性中中风死亡占60%。
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