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The Impact of “Good” and “Bad” Cholesterol on Heart Disease
By now many of us have heard that cholesterol actually exists in multiple forms – the most popular pair often referred to as the “good” and the “bad” – and the various types can affect our heart health differently. But a new report in the American Heart Association’s journal Circulation shows how each actually affects the likelihood of heart failure.
High−density lipoprotein or HDL cholesterol is known as the “good” variety, while the “bad” form, here designated non−HDL, consists of low−density lipoproteins (LDL) and triglycerides. Lead author Daniel Levy says that he and his team “hypothesized that there might be a direct effect of lipids on the function of heart muscle.”
Over 6,800 participants from the Framingham Heart Study were followed for about 26 years, beginning from the time they averaged 44 years of age. None suffered from any kind of heart problem at the study’s onset, but by its end, 680 of the participants suffered heart failure.
Those who had low levels of HDL cholesterol suffered from heart failure much more than those with higher levels of it – over twice as much, in fact. Likewise, participants with high levels of non−HDL cholesterol suffered from heart failure almost twice as often as those with lower levels. Even more striking was what the researchers saw when they factored in the effects of smoking, age, body mass index, sex, blood pressure, and diabetes. Now heart failure was 29% more likely to occur in those with high non−HDL cholesterol and 40% less likely to occur with high HDL cholesterol levels.
“The biggest surprise was the strength of the inverse relation of HDL to risk of heart failure,” Levy said.
He adds that the “study goes a step further in implicating cholesterol levels (both HDL and non−HDL) in heart failure and suggests that cholesterol−altering therapy may have long−term benefits in preventing heart failure above and beyond its effects on preventing myocardial infarction.”
Levy does caution that the study was not a randomized trial, so its implications should not technically change the guidelines doctors use to prescribe cholesterol−lowering drugs. Still, the study is a nice step in unraveling the roles of the various forms of cholesterol in heart disease, and provide a good jumping−off point for future studies.
December 25, 2009
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