‘Good’ cholesterol worsens for some adults: NIH study

A recent NIH study challenges the role of a routine measure of heart health. Testing for high-density lipoprotein, or HDL, cholesterol may not be as useful as previously thought when used to predict cardiovascular disease (CVD) risk in various groups of adults.

The study was recently published in the Journal of American College of Cardiology.

While low levels of HDL cholesterol predicted an increased risk of heart attack or related deaths for white adults, the same was not true for black adults. Additionally, higher HDL cholesterol levels were not associated with reduced cardiovascular disease risk for either group.

An association between HDL cholesterol levels and risk of CVD was first described in the 1970s in the Framingham Heart Study. “It’s been well accepted that low HDL cholesterol levels are detrimental, regardless of race,” Dr. Nathalie Pamir, a senior author of the NIH study, said in a statement. “Our research tested those assumptions.”

The Framingham study discovered an “inverse and linear association between plasma high-density lipoprotein cholesterol (HDL-C) concentration and [coronary heart disease (CHD)] risk,” the authors wrote, adding that nevertheless, the association was seen “in other mostly white European cohorts, whereas it was weaker or even absent in racially diverse cohorts.”

The new analysis included Black and white middle-aged adults without heart disease who had participated in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study from 2003 to 2007.

The team examined data from 23,901 US adults who were participants enrolled in REGARDS between 2003 and 2007, including information collected throughout a 10- to 11-year period. All participants shared similar characteristics, including age, cholesterol levels, and underlying risk factors for heart disease such as diabetes, high blood pressure, and smoking. During the study period, 664 black adults and 951 white adults experienced either a heart attack or a heart-related death.

The researchers wrote that “low HDL-C was associated with increased CHD risk” in white adults, confirming previous research, but that the same association was not found in black adults.

Other lipid parameters, “such as LDL-C and triglycerides, did not display race-specific behavior and were comparably associated with CHD risk in Black and white participants.”

That suggests that “the underlying biological mechanism by which HDL-C associates with incident CHD in white and black participants is different from that of other lipid risk factors,” the authors wrote.

They noted that the study findings expose weaknesses in the use of HDL cholesterol clinical risk category cutoffs. “Such categories might not apply to Black men and women, reducing their value in CHD risk assessment,” they added.

Another implication is that optimal amounts of HDL cholesterol may not provide cardiovascular benefits for either Black or white adults, the authors wrote.

Pamir also noted that there may be other ways in which HDL cholesterol supports heart health. The quality of HDL’s function in transporting excess cholesterol may be more important for supporting heart health than an individual’s HDL levels, she said.

“What I hope this type of research establishes is the need to revisit the risk-predicting algorithm for cardiovascular disease,” Pamir added.

Pamir and her team suggested that future research should focus on understanding the mechanisms that link HDL cholesterol to cardiovascular risk, and further examining how race affects these mechanisms.

“Race is a complex metric defined both by a social construct and a genetic construct, making it challenging to capture its full spectrum in a risk prediction algorithm,” the team wrote. “Collective data from recent years suggest that we should develop a population-wide risk estimation algorithm that works in other races as well.”

The recent study was not without its limitations, the group noted, with one being a limited number of fatal cardiovascular disease events per race.

Leave a Comment

Your email address will not be published. Required fields are marked *

%d bloggers like this: