A study funded by the National Institute of Health has found that high-density lipoprotein, HDL, also sometimes referred to as the ‘good’ cholesterol, may not be as much of a predictive tool for heart disease risk as scientists initially thought it to be.

Prior studies have established that higher HDL cholesterol levels are linked to a lowered risk of coronary heart disease, and are widely utilized as a form of heart disease risk assessment. However, these studies focused majorly on whites and the link remains unclear for other populations.

Now, the findings published in the Journal of the American College of Cardiology found that low HDL cholesterol levels were linked to a higher risk of heart attacks or heart attack-related deaths in white adults but not black adults. In addition to that, higher HDL cholesterol levels were not linked to the risk of these events in either group.

According to the study authors, it is widely known for low LDL cholesterol levels, or ‘bad cholesterol, to be significantly harmful irrespective of race or ethnicity.  This sparked curiosity in the researchers and pushed them to test this assumption. 

For the study, the researchers looked at data from a total of 23,901 study participants who were recruited in the Reasons for Geographic and Racial Differences in Stroke (REGARDS). The participants comprised self-reported black and white men and women who were 45 years and older and were enrolled in REGARDS from 2003 to 2007. Black and white participants had similar ages, levels of total cholesterol, hypertension, and diabetes drug use as well as smoking status. They were followed up every six months to detect likely cardiovascular events. 

During an average follow-up period of 10 to 11 years, a total of 1,615 cardiac events occurred. Of which 664 black adults and 951 white adults developed heart diseases. The team found that low-density lipoprotein cholesterol levels ‘modestly’ predicted heart disease risk in black and white adults. 

Importantly, this is the first study to discover that low HDL cholesterol levels predicted a higher risk of cardiovascular diseases in only white adults. It also counters previous studies suggesting that high HDL levels are not always linked to a decrease in heart diseases and should by all means be demoted. And on top of that, it may not be helpful with respect to heart health benefits in either race. This, therefore, reduces their value in heart disease risk assessments.

Meanwhile, current heart disease risk screening tools established solely for whites may misclassify risks in black adults and most likely hinder optimal prevention and management programs for cardiovascular diseases for this group.

“When it comes to risk factors for heart disease, they cannot be limited to one race or ethnicity,” said senior author of the study, Nathalie Pamir, Ph.D., an associate professor of medicine within the Knight Cardiovascular Institute at Oregon Health & Science University, Portland. “They need to apply to everyone. It could mean that in the future we don’t get a pat on the back by our doctors for having higher HDL cholesterol levels,” she concluded in the study.

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