The study found that while low levels of HDL cholesterol predict an increased risk of heart attack or related death in white adults, a medically long-accepted correlation factor, this is not the case for black adults.

A study found that high-density lipoprotein (HDL) cholesterol, commonly known as "good cholesterol", may not uniformly predict the risk of cardiovascular disease in adults of different races and ethnic backgrounds, as scientists once thought. This study was supported by National Institutes of Health (NIH).

study found that while low levels of HDL cholesterol predict an increased risk of heart attack or related death in white adults, a medically long-accepted correlation factor, this is not the case for black adults. Furthermore, higher HDL cholesterol levels had no relationship with the reduction in cardiovascular risk in both groups. The study was published on November 21 in the Journal of the American College of Cardiology.

low-density lipoprotein cholesterol, sometimes called "bad" cholesterol , constitutes most of the cholesterol in the human body. High levels of LDL cholesterol can increase the risk of heart disease and stroke . HDL (high density lipoprotein) cholesterol, sometimes called "good" cholesterol, absorbs cholesterol from the blood and brings it back to the liver. "Our goal is to understand this long-standing connection, namely labeling HDL as a beneficial cholesterol, and whether this is true for all populations," said Natalie Pamir, Ph.D., senior author of the study and associate professor of medicine at the Knight Cardiovascular Institute at the Oregon Health and Science University in Portland. "The low HDL cholesterol levels are harmful, which is recognized for no race, and previous studies have tested these hypotheses." To do this, Pamir and her colleagues reviewed data from 23,901 U.S. adults who participated in the geography and racial disparity study of strokes (REGARDS). Previous studies have shaped perceptions about "good" cholesterol levels and heart health, which were conducted in the 1970s through studies of most white adult research participants. In the current study, researchers were able to observe the overlap of cholesterol levels in black and white middle-aged people living around the country with no heart disease and future cardiovascular events.

study participants participated in REGARDS between 2003 and 2007, and the researchers analyzed the information collected over the 10-11 year period. Black and white study participants had similar characteristics such as age, cholesterol levels and potential heart disease risk factors, including diabetes , hypertension , or smoking. During this time, 664 black adults and 951 white adults experienced heart attacks or deaths related to heart attacks. Adults with elevated levels of low-density lipoprotein (LDL) cholesterol and triglyceride have a slightly increased risk of cardiovascular disease, which is consistent with previous studies.

However, this study found for the first time that lower HDL cholesterol levels only predict increased risk of cardiovascular disease in white adults. It also extends the results of other studies showing that HDL cholesterol levels are not always associated with reducing cardiovascular events. The REGARDS analysis is the largest study in the United States, showing that both black and white adults are like this, suggesting that higher than the optimal amount of "good" cholesterol may not bring cardiovascular benefits to both groups. "I hope this type of research establishes a risk prediction algorithm that needs to be reexamined by cardiovascular disease. This may mean that in the future we will not be deemed by doctors not to follow up on diagnosis and treatment because of having high HDL cholesterol levels." As researchers look at the role of HDL cholesterol in supporting heart health, they are exploring different theories. One is that mass is greater than quantity, which means that it is better to say that the functional quality of HDL is more important than having more HDL - picking up and transporting excess cholesterol from the body may be more important to support cardiovascular health.

They are also conducting microscopic studies on the properties of high-density lipoprotein cholesterol, including analyzing hundreds of proteins related to transporting cholesterol, and how different associations based on one protein or a set of proteins may improve cardiovascular health predictions. "HDL cholesterol has long been a mysterious risk factor for cardiovascular disease. These findings suggest that more in-depth research on the epidemiology of lipid metabolism, especially in how race changes or mediates these relationships," explained Sean Coady, deputy director of epidemiology at the National Heart, Lung and Hematology Institute (NHLBI), explains. "In addition to supporting ongoing and future studies of different populations to explore these links, these findings suggest that the use of cardiovascular disease risk calculators with high-density lipoprotein cholesterol may lead to inaccurate predictions for black adults.

"When it comes to risk factors for heart disease, they cannot be limited to one race or ethnic group," Pamir said. "They need to apply to everyone."