High HDL Levels May Not Protect the Heart

For decades doctors have been telling their patients that high levels of HDL, otherwise known as “good cholesterol,” can protect them from heart disease. But a new study suggests that having a lot of so-called good cholesterol doesn’t necessarily mean a lower risk of heart attack.

This does not mean that HDL levels have no effect.

An analysis of data from nearly 24,000 US adults showed that very low HDL cholesterol was associated with an increased risk of heart disease — in white adults, but not in black adults, researchers reported Monday in the Journal of the American College of Cardiology.

The new findings surprised the researchers, who originally designed their study to understand how cholesterol levels in black and white middle-aged adults without heart disease affect their future risks. Previous research on “good” cholesterol and heart disease involved mostly white adults.

“I didn’t expect that higher levels of HDL would not be protective,” said the study’s senior author, Nathalie Pamir, an associate professor of cardiovascular medicine at Oregon Health & Science University School of Medicine. “And I certainly didn’t expect the low level to have no predictive value for black adults.”

The new research, co-funded by the National Institutes of Health, is part of a growing body of evidence that disputes whether high HDL cholesterol levels are protective against heart disease, experts say, although people aren’t always getting the message.

“Those of us with high HDL are getting a pat on the back from our doctors,” said Pamir, a researcher with the Center for Preventive Cardiology at OHSU’s Knight Cardiovascular Institute. “We have been told that your HDL is good so don’t worry. You are safe.

Low-density lipoproteins, or LDL, contribute to fatty buildup in the arteries, which increases the risk of heart attack and stroke. It was long thought that high-density lipoprotein, or HDL, is protective because it carries cholesterol to the liver, where it is disposed of.

What is clear now is that high HDL adds to the total cholesterol number.

“It’s still cholesterol at the end of the day,” Pamir said. “More and more studies are coming out showing that HDL levels above 80 are detrimental with respect to cardiovascular outcomes.”

The findings suggest that the algorithms used to calculate a person’s risk of coronary heart disease need to be adjusted because they currently show a lower risk when HDL is high, Pamir said.

Risk calculations also need to take race into account, he said, adding that the difference seen in black adults may be due to socioeconomic factors rather than genetics.

What is a healthy cholesterol level?

Right now, a major focus should be on the total cholesterol number, Pamir said.

Cholesterol levels are measured in milligrams per deciliter of blood (mg/dL). According to the American Heart Association, the optimal total cholesterol level for an adult is around 150 mg/dL, with an LDL level of 100 mg/dL or less.

To take a closer look at HDL’s effect on coronary heart disease risk, Pamir and colleagues turned to data from the Causes of Geographic and Racial Differences in Stroke (REGARDS) study. The researchers focused on 23,901 middle-aged black and white REGARDS participants who were enrolled from 2003 to 2007 and who had no heart disease at baseline.

During an average of 10.7 years of follow-up, 1,615 cardiovascular events occurred, 41.1% in black participants and 45.5% in women. High LDL and levels of another fat known as triglyceride were associated with an increased risk of coronary heart disease in black and white participants.

Low HDL levels were associated with an increased risk of coronary heart disease in white participants, but not black participants.

Clinical director of the Center for the Prevention of Heart Disease in the Leon H. Cheney Division of Cardiology at NYU Langone Health, Dr.

“Frankly, on a daily basis someone comes into my office with an HDL of 80 or 90,” said Weintraub, who was not involved in the new research. “When I tell them it doesn’t mean they’re bulletproof, they’re disappointed because their doctor told them not to worry about bad cholesterol because the good cholesterol was so much better.”

The idea that HDL was protective was so accepted, Weintraub said, that drug companies developed drugs that “raised HDL levels by 100%, and people died.”

High HDL levels are usually a marker of a healthy lifestyle, said cardiology expert Dr. Robert Rosenson.

“People with higher HDL levels are less likely to be overweight, more likely to be active, less likely to be smokers and have prediabetes,” said Rosenson, director of lipids and metabolism at Mount Sinai Health System in New York. less likely to happen.” who was not involved in the new study.

Still, Rosenson called the new research important because patients with high HDL levels may not be receiving cholesterol-lowering drugs.

Another important finding is the difference in cardiovascular risk between black and white patients, said Dr. Leslie Chow, interventional cardiologist and section head of preventive cardiology and cardiac rehabilitation at the Cleveland Clinic.

“Underrepresented minority groups should demand more clinical (trial) representation,” said Cho, who was not involved in the new research. “It’s really important.”

Judy Silverman contribution,

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