A new study was released earlier this week that says HDL–otherwise known as “good cholesterol” by everyone from doctors to the CDC, because of its association with a lower risk of heart disease–may not do much to lower your risk of heart disease. This is particularly troublesome news for pharmaceutical companies and their researchers, who’ve invested huge sums of money and time searching for drugs to raise HDL levels, but it’s not altogether bad news for our health, as some headlines have made it out to be. Mostly, it just means that instead of looking for ways to manipulate HDL levels directly, we should be looking at the genes and habits of people with high HDL to figure out what’s really boosting their heart health.
Conventional wisdom says that high LDL (or “bad”) cholesterol levels increase heart disease risk, while high HDL (“good”) levels lower it. The study, led by the director of preventive cardiology at Massachusetts General Hospital and geneticist, Dr. Sekar Kathiresan, examined genetic data for tens of thousands of people, looking specifically at genetic variations that increase changes of having high HDL or high LDL. For those with a genetic inclination towards high LDL, the result wasn’t surprising: They also had a high risk of developing heart disease. But those who were genetically predisposed to having high HDL didn’t have any lower chance of developing heart disease.
For drug companies, this study may not be entirely new news: At least three recent clinical trials of HDL-raising drugs have shown their failure to lower heart disease risk. But many doctors and researchers are still digesting what the implication–that “good” cholesterol doesn’t really lower risk of heart disease–means for their industry, and their patients.
Dr. Michael Lauer, director of the division of cardiovascular sciences at the National Heart, Lung and Blood Institute (who wasn’t involved in the study), told the New York Times that it proves a fundamental flaw in our understanding of “good” cholesterol:
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. We need to encourage basic laboratory scientists to figure out where HDL fits in the puzzle — just what exactly is it a marker for.
But Dr. Steven Nissen, chairman of cardiovascular medicine at the Cleveland Clinic (who wasn’t involved in the study, but does research HDL-raising drugs) said that he’s “an optimist,” and believes that HDL is complicated, but could still prove to have a direct impact on heart disease.
Researchers and drug companies will likely continue to explore the positive effect of raising HDL levels, but some doctors are saying that, at least for now, it may not best the best way for patients to improve their health. Low HDL levels may indicate heightened risk of heart disease, explained Dr. Kathiresan (the study’s lead author), but raising it doesn’t necessarily lower your risk.
But on the bright side, this doesn’t mean that patients have no agency: The study still found a very strong correlation between LDL genetic markers and heart disease risk–which means lowering your “bad” cholesterol is still a worthy pursuit.