New studies suggest that HDL doesn’t have the same beneficial effect on different ethnicities.
A study funded by the US National Institutes of Health has found that high-density cholesterol (HDL), often called the “good cholesterol,” may not be as effective as scientists once believed at predicting cardiovascular disease risk uniformly. among adults of different races and ethnicities.
HDL is commonly called “good cholesterol” because it is a lipoprotein not made up of “pure cholesterol”, in fact it is also made up of various specific proteins that perform the function of transporting some fats in the blood. There are various types of lipoproteins in the body and each fulfills a specific task.
Remaining in the “world” of cholesterol, we must consider that it is a lipid, therefore poorly soluble in water, therefore, to be transported in the bloodstream it needs to bind to specific lipoproteins. Cholesterol binds mostly to low-density lipoprotein, or LDL . Excess LDL-bound cholesterol tends to accumulate in the arteries, forming increasingly dense aggregates that lead to loss of elasticityof these blood vessels and can cause serious damage especially to the heart (heart attack) or brain (stroke). HDL, high-intensity proteins, are considered beneficial because they clean out the arteries by transporting excess cholesterol and transferring it to the tissues (especially the liver), where it is eliminated. Thus, the higher the level of HDL in the blood, the lower the risk of developing atherosclerosis and all the other negative consequences of hypercholesterolemia.
The research, published in the Journal of the American College of Cardiology, however, questions this assumption which has led over the years to consider the ratio between HDL-LDL more important than the level of cholesterol in the blood. Research has found that while low HDL cholesterol levels predict an increased risk of heart attack or related death for Caucasian adults, the same is not true for Black adults.. Furthermore, higher levels of HDL cholesterol were not associated with a reduction in the risk of cardiovascular disease for either group. The previous studies that shaped perceptions of cholesterol levels as “good” were done in the 1970s through research conducted with a majority of white adult participants.
high HDL doesn’t necessarily mean you’re safe and sound
“The goal was to understand this long-established link that labels HDL as the beneficial cholesterol and whether this is true of all ethnicities,” said Nathalie Pamir, Ph.D., senior author of the study and an associate professor of medicine. at the Knight Cardiovascular Institute of the Oregon Health & Science University in Portland. To do so, Pamir and his colleagues looked at data from 23,901 US adults who participated in the Reasons for Geographic and Racial Differences in Stroke Study (REGARDS). For the study, the researchers were able to observe how the cholesterol levels of middle-aged black and white adults without heart disease, residing across the country, still overlapped with future cardiovascular events.
The study participants, both black and white, had similar characteristics, such as age, cholesterol levels and risk factors associated with heart disease, including diabetes, high blood pressure and smoking. During the data collection period (2001 to 2007), 664 black adults and 951 white adults experienced a heart attack or heart attack-related death. Adults with higher levels of LDL cholesterol and triglycerides had a modestly increased risk of cardiovascular disease, consistent with previous research findings.
However, the study was the first to find that lower HDL cholesterol levels predicted increased risk of cardiovascular disease only for white adults . This research also confirms and expands on the findings of other research demonstrating that high HDL cholesterol levels are not always associated with a reduction in cardiovascular events. The REGARDS analysis was the largest US study to show that higher-than-optimal amounts of “good” cholesterol may not provide cardiovascular benefits to either ethnic group.
“I hope this type of research establishes the need to revise the risk prediction algorithm for cardiovascular disease,” Pamir said. “It could mean that in the future, our doctors will no longer pat us on the back for having higher levels of HDL cholesterol.”
Pamir explained that researchers are investigating the role of HDL cholesterol extensively, exploring different theories. One of these is that quality prevails over quantity . In other words, rather than just monitoring the amount of HDL, it may be more important to look at the quality of HDL’s function in collecting and transporting excess cholesterol from the body.
The authors conclude that ongoing and future research with populations of different ethnicities should be supported to explore the connections, and that “When it comes to risk factors for heart disease, you can’t limit yourself to one race or ethnicity.” Pamir said. “They must apply to everyone”.
- Race-Dependent Association of High-Density Lipoprotein Cholesterol Levels with Incident Coronary Artery Disease. (jacc.org)