THE ESSENTIAL
- People with high levels of good cholesterol often develop less cardiovascular disease.
- According to the researchers, the number of HDL particles is a better predictor of heart risks than the generally used measurement.
- “But if you are not white, it is not that simple,” warn the scientists.
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Cholesterol is a waxy substance used by the body to make hormones and keep cells functioning properly. For years, high density lipoprotein (HDL) cholesterol has been nicknamed “good cholesterol”. In fact, it displaces fats and other cholesterol molecules outside the arterial walls, unlike the cholesterol of low density lipoproteins (LDL), which is called “bad cholesterol”. In particular, studies have shown that people with high HDL cholesterol generally develop fewer cardiovascular diseases than others. In a new study, the results of which appeared in Circulation, American researchers have found that the particle number of HDL, a measure little used to calculate the level of good cholesterol, is a more reliable predictor of the risk of heart attack and stroke than the standard measure. For black people, however, the prediction is more complicated.
For their research, scientists at UT Southwestern (United States) gathered information from people who participated in four major national studies on atherosclerosis (accumulation of fatty plaques on the walls of blood vessels) and kidney disease and vascular. In total, these studies involved 15,784 people followed for an average of 8 to 12 years. Among the participants, 54% were men, 22% were black and their average age was 56 years.
“Previous studies have looked at HDL levels in the general population, explains doctor Anand Rohatgi, associate professor of internal medicine at UTSW. But we do know that biology sometimes differs by gender and race, which is why we thought it was important to distinguish what is going on in these populations, as well as how HDL is associated with stroke. , which have been understudied. ”
“If you’re not white, it’s not that simple”
The researchers found that people with HDL-P levels, which correspond to the number of HDL particles circulating in the blood, had the highest risk of heart attack and stroke 37% lower than that people with lower levels. Among women, this association was more marked. Indeed, those with the highest HDL-P levels had a 49% reduction in heart attacks and a 46% reduction in strokes. If the standard test, which calculates HDL-C levels, predicts the risk of heart attack in the whole group, it is not associated with strokes, say the researchers.
In contrast, in black participants, neither the HDL-C test nor the HDL-P were linked to the risk of heart attack. “If you are white, low HDL cholesterol remains a strong predictor of heart attack and stroke risk, and that has not changed. ”, commente Anand Rohatgi. But if you’re not white, it’s not that simple. ”
Understanding more about how HDL can help predict disease, and how this association differs across populations, could go a long way in reducing rates of cardiovascular disease.
“These risk markers are really relevant in primary care and everyday cardiology ”, comments Dr. Kavisha Singh, a USSW cardiology researcher and lead author of the study. Doctors use cholesterol levels to decide whether a patient should take medication or not ”, she recalls.
Get tested every five years
Building on these results, the team is planning future studies on the functionality of HDL particles in black people and how HDL-P can be used clinically. Finally, it will be a question of determining whether HDL-P could be associated with specific subtypes of stroke.
When the bad cholesterol is too high, it can promote atherosclerosis (accumulation of fatty plaques on the walls of blood vessels), which increases the risk of stroke, heart attack and peripheral arterial disease. In France, 19% of adults have hypercholesterolemia (LDL cholesterol greater than 1.6 g / l). This phenomenon is believed to cause one in two heart attacks.
From where the importance of getting tested every five years during a lipid check-up, when we are in good health. The test is carried out by a fasting blood test and a biological analysis, explains the French Federation of Cardiology. Recently, a study appeared in the magazine The Lancet, showed in particular that giving a treatment to lower the level of bad cholesterol in people under 45 with too high a rate would reduce these cardiovascular risks later in life.
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