Why a different way to measure 'good' cholesterol may be more useful

A new study has found that measuring “good” cholesterol in a different way may predict the chances of stroke or heart attack more accurately.

The Centers for Disease Control and Prevention (CDC) highlight that heart disease is the leading cause of death among almost all groups of people in the United States; 1 in 4 deaths in the country result from this type of illness.

Although there are ongoing debates about the relationship between cholesterol and heart health, the CDC distinguish between good and bad cholesterol.

Good cholesterol is better-known as high-density lipoprotein (HDL) cholesterol. Cholesterol travels through the body on lipoproteins, and this type brings cholesterol to the liver, which then removes it from the body.

Bad cholesterol is called low-density lipoprotein (LDL) cholesterol. This is the main type, and the medical community believes that it increases the risk of cardiovascular issues, such as heart attacks and strokes.

When there is too much LDL in the body, it can collect to form plaques in blood vessels. This raises blood pressure, which increases the risk of serious cardiovascular disease.

Increased amounts of HDL, on the other hand, are associated with a lower risk of cardiovascular disease.

Now, new research suggests that an alternate way of measuring HDL may more accurately predict the risk of heart attacks and strokes.

The team behind the findings, published in the journal Circulation, also notes that neither the traditional nor the new measure showed any strong association between HDL cholesterol levels and heart attack among Black participants.

Different ways of measuring HDL

Traditionally, HDL levels are measured by determining the total amount of cholesterol being carried by HDL particles.

However, recent research has suggested that measuring the number of particles of HDL (HDL-P), rather than the total amount of cholesterol that the particles carry (HDL-C) may be a better way of determining the association between HDL and cardiovascular diseases.

The authors of the present study wanted to develop this research further to see the differences in the abilities of the two measures to predict cardiovascular disease.

They also wanted to test whether being Black or white made any difference to the relationship between HDL and the risk of cardiovascular issues.

According to Dr. Anand Rohatgi, an associate professor and preventive cardiologist at the University of Texas Southwestern Medical Center, “Previous studies have looked at HDL levels in the population as a whole.”

“But we know that sometimes biology differs by gender and race, so we thought it was important to separately tease apart what’s happening in those populations, as well as how HDL is associated with stroke, which has been understudied,” he adds.

Higher HDL-P, lower cardiovascular risk

To conduct their study, the researchers drew on four large studies that contained data about the different HDL measures as they relate to cardiovascular issues. These studies were the Dallas Heart Study, the Atherosclerosis Risk in Communities study, the Multi-Ethnic Study of Atherosclerosis, and the Prevention of Renal and Vascular End-stage Disease study.

In total, they included 15,784 participants, who had been tracked for an average of 8–12 years. Of the total number, 46% were male, 22% were Black, and the average age was 56.

According to Dr. Kavisha Singh, first author of the study and a research fellow at the university, “By combining all these large existing cohorts, we had enough numbers to look at these populations that had been understudied in the past.”

The authors found that participants with the highest HDL-P levels had a 34% lower risk of strokes and a 37% lower risk of heart attacks, compared with participants who had the lowest HDL-P levels.

The association was even stronger among women: The highest HDL-P levels were associated with a 46% reduction in strokes and a 49% reduction in heart attacks, compared with the lowest levels.

HDL-C levels, the traditional measure of this form of cholesterol, were associated with heart attacks but not strokes, suggesting that HDL-P may be the better measure of the effects of cholesterol on a person’s heart health.

Interestingly, when the researchers looked only at the data from Black participants, they found neither HDL-P nor HDL-C robustly predicted heart attacks.

Dr. Rohatgi notes:

“If you’re white, low HDL cholesterol is still a powerful predictor of heart attack and stroke risk, and that has not changed. But if you’re not white, it’s not that straightforward.”

The study has its limits: Understanding the difference in the association between HDL and heart health among Black and white participants will require more research. While biological differences could account for the variance, issues related to structural racism could also play a role, as could other, still unidentified factors.

Nonetheless, cholesterol levels can be a key piece of information for a clinician, and so using the best measurements is important. As Dr. Singh explains: “These risk markers are really relevant in everyday primary care and cardiology. Doctors use cholesterol levels to make decisions like whether a patient goes on medication or not.”

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