Study casts doubt about role of HDL ‘good’ cholesterol in heart health

Experts said the findings call for a reevaluation of how HDL is used to predict people’s risk of developing heart disease. Photo by Steve Collender / Shutterstock

Blood levels of HDL, the well-known “good” type of cholesterol, may not make a big difference when it comes to heart health, especially for black people, a major new study suggests.

The study of nearly 24,000 US adults found that lower levels of HDL were associated with a somewhat higher risk of heart attack in white men. However, this was not the case for black adults.

Meanwhile, higher HDL levels — traditionally lauded as heart-healthy — made no difference in cardiovascular risk for black or white adults.

Experts said the findings call for a reevaluation of how HDL is used to predict people’s risk of developing heart disease. More broadly, he said, researchers need to find out whether different “traditional” heart disease risk factors have the same effect on all people.

“We need to expand our understanding of risk factors for all racial and ethnic groups,” said senior researcher Nathalie Pamir, associate professor of medicine at Oregon Health & Science University in Portland.

That understanding, he said, translates into treatment guidelines. “And our guidelines have to work for everyone,” Pamir said.

HDL, or high-density lipoprotein, first gained its reputation as “good” cholesterol with the Framingham Heart Study. In the 1970s, it found an association between higher HDL levels and a lower risk of heart attack.

The Framingham Study is a major, still-ongoing research project: Decades ago, it identified several factors now believed to be important in whether people develop heart problems or suffer a stroke: high blood pressure, “bad” High levels of LDL cholesterol, smoking and obesity increase those risks, while exercise and high HDL lower the odds.

Today, HDL is considered very low if it is less than 40 mg/dL for men or 50 mg/dL for women. A value between those numbers and 59 mg/dL is considered normal, but people are encouraged to shoot for a “desirable” 60 or higher.

The problem is that all of the Framingham participants were white. Some recent studies with more racial diversity have raised the question of whether low HDL is “bad” for everyone’s heart.

The new findings, Pamir said, show that for black Americans, this idea doesn’t hold up.

The study, published Monday in the Journal of the American College of Cardiology, included 23,901 US adults age 45 and older who were initially free of coronary heart disease. This refers to heart disease caused by a build-up of artery-clogging “plaques”.

About 42% of participants were black, and 58% were white.

Over the next decade, just over 1,600 people had heart attacks or died from coronary heart disease. It turned out that low HDL predicted a marginally higher risk of heart trouble, but only in white people: Those with low levels had a 22% higher risk than white participants with normal HDL.

In black adults, low HDL had no effect on heart disease risk. What’s more, high HDL offered no protection to either.

The findings on high HDL aren’t surprising, Pamir said: Trials testing HDL-raising drugs haven’t found heart protection either.

“But the dogma is still ‘high HDL is good,'” Pamir said. “You still get a pat on the back if your HDL is high.”

The consequences, however, may be more than an unwanted pat on the back, he said. Doctors use HDL along with other risk factors, such as high blood pressure and high LDL, to assess patients’ risk of developing heart disease over the next 10 years. And that guides treatment decisions, such as whether to prescribe a statin.

For black patients, however, neither low nor high HDL is a useful measurement.

If the findings lead to a change in how HDL is used, that would be a good thing, said Dr. Keith Ferdinand, a cardiologist and professor at Tulane University School of Medicine in New Orleans.

For black patients, more weight should be given to risk factors such as high blood pressure, obesity and high LDL, according to Ferdinand, who wrote an editorial published with the study.

But ultimately, he said, social disparities are the main reason why black Americans are a third more likely to die from heart disease or stroke than white Americans.

“It’s not enough to just tweak HDL,” Ferdinand stresses. “We need to address our structural inequalities.”

He added that when people can’t afford healthy food, have no safe places to exercise, face chronic stress, and can’t pay for drugs, they are at a higher risk of developing heart disease. have – and have a hard time managing it when they do.

For low HDL, Pamir said the recommended steps to raise it are good ones: These include exercise, quitting smoking and avoiding “trans” fats in processed foods.

So black adults with low HDL should keep doing those things, Pamir said. However, they don’t need to stress about increasing their numbers.

The study was funded by the US National Institutes of Health.

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The American Heart Association offers advice on a heart-healthy lifestyle.

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