HDL胆固醇通常被视为“好”胆固醇，因为一般认为体内HDL胆固醇水平高，发生心肌梗塞的风险就小。本周四发表在《柳叶刀》杂志的一项研究，发现并没有任何证据表明遗传上具有高HDL胆固醇水平人，对心肌梗塞的易感性就低。请看CBC的详细报道。

'Good' cholesterol's heart benefits challenged

 Drugs to raise HDL can't be assumed to reduce heart attack risk CBC News Posted: May 17, 2012 3:46 PM ETLast Updated: May 17, 2012 3:42 PM ET

 

Having naturally high levels of "good" cholesterol doesn't lower the risk of heart attacks as believed.

LDL cholesterol is referred to as "bad" cholesterol because when there's too much, it promotes the build-up of plaque in artery walls.

HDL cholesterol is known as "good" cholesterol because higher concentrations have been associated with lower risk of heart attacks in observational studies.

Tests suggested about 2.6 per cent of the population was genetically predisposed to have higher concentrations of HDL cholesterol in their blood. (Jose Leiva/Sun Journal/Associated Press)

The hoped for benefits of increasing high-density lipoprotein or HDL cholesterol for lowering heart attack risk haven't panned out in randomized trials of experimental drugs.

According to conventional wisdom, those who inherit genetic variants for higher HDL levels should have lower cardiovascular risk. When researchers tested 116,000 people, they found 2.6 per cent of them were genetically predisposed to have higher concentrations of HDL.

These people did have higher levels of HDL, but there was no evidence that they actually enjoyed a lower susceptibility to heart attack, also called myocardial infarction.

"Some genetic mechanisms that raise plasma HDL cholesterol do not seem to lower risk of myocardial infarction," Dr. Sekar Kathiresan of Harvard Medical School in Boston and his co-authors concluded in Thursday's issue of the medical journal The Lancet.

"If an intervention such as a drug raises HDL cholesterol, we cannot automatically assume that risk of myocardial infarction will be reduced."

Heart-healthy lifestyle

The findings refute the thinking that low HDL plays a causal role in heart disease, Steve Humphries and his colleagues of University College London in the UK said in a journal commentary.

The observation from the genetic analysis "calls into question whether raising of HDL cholesterol therapeutically would translate into the expected clinical benefit," the commentators said.

Eating foods such as walnuts, almonds and salmon seems to help cholesterol levels.

The vitamin niacin was also proposed as a way of raising HDL but a U.S.-government funded trial into it was stopped early last year when those taking it showed no reduction in heart attacks and strokes.

The British Heart Foundation said the relationship between HDL and heart attack risk is complex and more research is needed to understand how it interacts with other risk factors.

"What we do know is that having too much harmful cholesterol in your blood can increase your risk of getting cardiovascular disease," said Shannon Amoils, the group's research advisor.

"A healthy lifestyle is vital to improve your overall cholesterol levels and protect your heart. Cutting down on fatty and sugary foods, as well as reducing the amount of alcohol you drink, will all have a beneficial effect on your heart health."

Many of the authors have received grants or are employed by pharmaceutical companies selling medications to lower LDL cholesterol levels.

 

http://www.cbc.ca/news/health/story/2012/05/17/cholesterol-good-hdl-heart-attacks.html

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