For decades now, high levels of HDL (high-density lipoprotein) cholesterol — also called “good” cholesterol — have been said to lower the likelihood for heart disease and stroke, per the Centers for Disease Control and Prevention (CDC). New research, however, challenges HDL’s role in predicting cardiovascular risk.
Published this month in the Journal of the American College of Cardiology, the study — which was supported by the National Institutes of Health — confirmed that low levels of HDL cholesterol indicated a greater risk of heart attacks or related deaths among white adults — although that did not prove to be the case for Black adults.
In addition, the investigation noted that higher HDL cholesterol levels did not appear to be associated with any cardiovascular benefit in either white or Black participants.
“The goal was to understand this long-established link that labels HDL as the beneficial cholesterol, and if that’s true for all ethnicities,” said Nathalie Pamir, PhD, a senior author of the study and an associate professor of medicine within the Knight Cardiovascular Institute at Oregon Health and Science University in Portland, in a statement. “It’s been well accepted that low HDL cholesterol levels are detrimental, regardless of race. Our research tested those assumptions.”
Dr. Pamir and her collaborators analyzed data on 23,901 Black (43.2 percent) and white (57.8 percent) adults age 45 and older who participated in the Reasons for Geographic and Racial Differences in Stroke Study (REGARDS), a project focusing on stroke risk factors. Over an average of 10 years of follow-up, 664 Black and 951 white participants experienced a heart attack or heart attack–related death.
Study authors observed that both Black and white adults with increased levels of LDL (low-density lipoprotein) cholesterol (sometimes called “bad” cholesterol) and triglycerides (a type of fat in the blood) had modestly increased risks for coronary heart disease, which corresponds with findings upheld by the CDC and other health sources, such as the American Heart Association.
Results also showed that high HDL cholesterol levels were not always linked with reduced cardiovascular events in both Black and white study participants. The findings back up growing evidence that higher than optimal amounts of “good” cholesterol may not provide cardiovascular benefits, as noted in a release by the European Society of Cardiology.
HDL cholesterol has been considered “good” because the HDL molecule is involved in the transport of cholesterol from the blood and blood vessel walls to the liver and ultimately out of the body, thereby reducing the risk of clogged arteries and atherosclerosis. In some cases, however, HDL may be too much of a good thing. A scientific paper published in 2021 in the journal Biomedicines said “it appears that higher HDL-C is not necessarily protective against cardiovascular disease and it can even be harmful in extremely high quantities.”
Mounting research may change the way HDL is used as a measure of heart health. “It could mean that in the future we don’t get a pat on the back by our doctors for having higher HDL cholesterol levels,” Pamir said.
Some Heart Health Measures May Be Influenced by Race
In addition, this current analysis found that lower HDL cholesterol levels only predicted increased cardiovascular disease risk for white and not Black adults. The researchers highlighted that established perceptions about “good” cholesterol levels and heart health have largely been based on studies involving mostly white participants, and such measures may be race dependent.
“Our race-dependent observations indicate that the underlying biologic mechanism by which HDL cholesterol associates with incident coronary heart disease in white and Black participants is different from that of other lipid [fat-like substances in the blood] risk factors,” wrote the authors. “Our findings [regarding HDL measures] expose the weaknesses in their use, because such categories might not apply to Black men and women, reducing their value in coronary heart disease risk assessment.”
A deeper dive into this topic is warranted as using HDL cholesterol could lead to inaccurate predictions for Black adults, according to Pamir and her colleagues.
“When it comes to risk factors for heart disease, they cannot be limited to one race or ethnicity,” she said. “They need to apply to everyone.”