It's long been thought that improving your high-density lipoprotein (HDL), or 'good' cholesterol, can help lower your risk of heart disease. However, new research suggests that may not be the case after all, prompting scientists to say it's time to go back to the drawing board.
A new genetic study published in the medical journal The Lancet suggests that people with high levels of HDL do not have a decreased risk of developing heart disease. The researchers in the study looked at 170,000 individuals total, splitting them into two groups: those who have a particular gene variation that boosts HDL, and those who do not. After studying up to 15 genetic variations, called single nucleotide polymorphisms (SNP), researchers discovered that even though the carriers of these variations had HDL levels that were higher than non-carriers, they had the same risk of developing heart disease as those without the genes. For example, carriers of one SNP had HDL levels that were 10 percent higher than most people, an elevation that's expected to reduce heart attack risk by 13 percent. But the study found they actually had the same risk as those without the SNP.
"It's been assumed that if a patient, or group of patients, did something to cause their HDL levels to go up, then you can safely assume that their risk of heart attack will go down," said senior author Sekar Kathiresan, director of preventive cardiology at MGH, associate professor of medicine at Harvard Medical School, and an associate member of the Broad Institute in a press release. "This work fundamentally questions that."
This new research may also call into question the benefits of taking medication to raise HDL levels.
“The current study tells us that when it comes to HDL we should seriously consider going back to the drawing board, in this case meaning back to the laboratory,” Dr. Michael Lauer, director of the division of cardiovascular sciences at the National Heart, Lung and Blood Institute, told the New York Times. “We need to encourage basic laboratory scientists to figure out where HDL fits in the puzzle—just what exactly is it a marker for.”
Although more research may be needed to explain these findings about HDL further, health experts maintain that lowering your low-density lipoproteins (LDL), can still help to decrease your risk of developing heart disease.