The widely held concept that blood levels of “good” cholesterol can indicate heart disease risk is not equally true for blacks and whites, and the measure itself may be less important than previously thought, according to a US study published Monday.
Different types of cholesterol are thought to have both healthy and harmful effects.
Low levels of so-called “good” high-density lipoprotein (HDL) cholesterol were linked to a higher chance of developing heart problems in a long-term study — but only in white participants, a study published in the Journal of the American College of Cardiology found.
Contrary to popular belief, low HDL levels do not increase the risk of heart disease in black people, researchers say.
However, among whites, those with HDL levels below 40 milligrams per deciliter had a 22% higher risk of coronary heart disease compared with those with higher HDL levels.
The researchers found that high HDL levels (above 60 mg/dL), which are considered protective, were not associated with a lower risk of coronary heart disease in either race.
“Usually in the doctor’s office, those of us with higher HDL levels get a pat on the back” for being at lower risk, said study leader Natalie Pamir of Oregon Health & Science University in Portland. “Instead of patting people on the back with high HDL, doctors should do nothing or say, ‘We don’t know what that means.'”
High levels of “bad” low-density lipoprotein (LDL) cholesterol, which is commonly treated with widely used statins such as Lipitor, and triglycerides were associated with an increased risk of heart disease in both races, her team found.
The study, funded by the National Institutes of Health, collected data for about 10 years from nearly 24,000 US adults, about 42% of whom were black.
Participants of both races were similar in age, cholesterol levels and other heart disease risk factors, the researchers noted.
The first studies that shaped perceptions of healthy cholesterol levels overwhelmingly involved white American participants, Pamir said. “Our study calls into question the available biomarkers that we use to assess risk because they were developed without considering all races.”
Dr. Keith Ferdinand of Tulane University in New Orleans, who was not involved in the study, warned in an editorial that using HDL cholesterol levels to assess risk “may inaccurately estimate and possibly misclassify risk (of coronary heart disease) in black adults and become a barrier to optimal care.”
Ferdinand wrote that the best estimates can be obtained by measuring the amount of calcium that builds up in patients’ arteries and monitoring cholesterol levels, called Lp(a).
In all cases, he added, regardless of biomarker levels, “therapeutic lifestyle changes are the foundation of prevention.”
