As people strive to maintain high levels of "good" cholesterol in their diet, new research has revealed that high-density lipoprotein (HDL) cholesterol may not be effective in "uniformly predicting cardiovascular disease risk" for adults belonging to all races and ethnic backgrounds.
A National Institutes of Health (NIH)-supported, published in the Journal of the American College of Cardiology, found that while low levels of HDL cholesterol predicted an increased risk of heart attacks or related deaths for white adults - a long-accepted association, but the same was not true for Black adults.
Additionally, higher HDL cholesterol levels were not associated with reduced cardiovascular disease risk for either group.
"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, associate professor of medicine within the Knight Cardiovascular Institute at Oregon Health & Science University, Portland.
"It's been well accepted that low HDL cholesterol levels are detrimental, regardless of race. Our research tested those assumptions," Pamir added.
To reach this conclusion, Pamir and her colleagues reviewed data from 23,901 adults who participated in the Reasons for Geographic and Racial Differences in Stroke Study (REGARDS).
For the current study, researchers were able to look at how cholesterol levels from Black and white middle-aged adults without heart disease who lived throughout the country overlapped with future cardiovascular events.
The study was the first to find that lower HDL cholesterol levels only predicted increased cardiovascular disease risk for white adults.
It also expands on findings from other studies showing that high HDL cholesterol levels are not always associated with reduced cardiovascular events.
"What I hope this type of research establishes is the need to revisit the risk-predicting algorithm for cardiovascular disease," Pamir said. "It could mean that in the future we don't get a pat on the back from our doctors for having higher HDL cholesterol levels."
As researchers study HDL cholesterol's role in supporting heart health, they are exploring different theories.
One is quality over quantity. That is, instead of having more HDL, the quality of HDL's function - in picking up and transporting excess cholesterol from the body - may be more important for supporting cardiovascular health.
"HDL cholesterol has long been an enigmatic risk factor for cardiovascular disease," said Sean Coady, a deputy branch chief of epidemiology within the National Heart, Lung, and Blood Institute (NHLBI)'s Division of Cardiovascular Sciences.
The findings suggest that a deeper dive into the epidemiology of lipid metabolism is warranted, especially in terms of how race may modify or mediate these relationships.
"When it comes to risk factors for heart disease, they cannot be limited to one race or ethnicity," said Pamir. "They need to apply to everyone."