Cholesterol Boost May Not Protect Your Heart

Increasing HDL cholesterol may not prevent heart attacks

(RxWiki News) It's widely believed that boosting your good HDL cholesterol cuts your risk of a heart attack. A genetic study suggests that might not necessarily be the case.

The large gene study found that, when examined together, 15 HDL cholesterol-increasing variants did not reduce the risk of a heart attack.

"Exercise regularly to receive an overall cholesterol benefit."

Senior author Sekar Kathiresan, MD, director of preventive cardiology at Massachusetts General Hospital, an associate professor of medicine at Harvard Medical School, and an associate member of the Broad Institute, noted there has been an assumption that if patients increase HDL levels, they can safely assume they will be rewarded with a reduced heart attack risk.

He said the findings of the study question that theory.

Previous research has suggested that the higher the levels of HDL cholesterol, the lower the heart attack risk. HDL has been suspected of offering a protective benefit by removing cholesterol from areas where it can cause damage.

However, this has been tough for scientists to prove, in part because there are no drugs that elevate HDL so it has been difficult to conclude that the potential good cholesterol boost could offer added protection.

During the study researchers studied the genes of about 170,000 individuals. Specifically they looked at 15 naturally occurring genetic variations to examine the connection between HDL cholesterol and heart attack risk.

Researchers studied two groups of participants, including those that had a particular gene variant and those who did not. The goal was to use two very large groups, expected to be similar, except for the specific gene of interest.

The results caught researchers off guard. Those who carried a particular variation in a gene called endothelial lipase had HDL levels that were elevated by about 10 percent, which they would expect to prompt a 13 percent lower risk of heart attack. However, these participants showed no difference in heart attack risk compared to people without the variant.

Though the findings were surprising, researchers still emphasize that HDL is a strong biomarker that can be used to pinpoint a person's heart attack risk.

"[HDL is] quite useful in identifying individuals at higher risk of having a heart attack in the future," said Dr. Kathiresan. "But we have shown that you cannot assume that raising HDL by any mechanism will help patients. Perhaps other mechanisms exist that can lower risk, but we will need to keep searching for them."

This study, funded by the National Institutes of Health, The Wellcome Trust, European Union, British Heart Foundation and the German Federal Ministry of Education and Research, was recently published in the journal, The Lancet.

Review Date: 
May 18, 2012