HDL ‘good’ cholesterol is not always good for heart health

“Good” and “bad” cholesterol: these are the long-starred characters in the saga of heart health. But in a twist to the larger theme, “good” football, it turns out, isn’t always good.

In the last dozen years or so, research on the particles that carry so-called good cholesterol — known as high-density lipoprotein, or HDL — has presented a much more nuanced and conflicting story about HDL’s role in cardiovascular disease.

And a new, great interest brings a new doubt. High levels of HDL cholesterol were not associated with protection against heart disease in black or white participants, researchers reported Nov. Journal of the American College of Cardiology. For low levels of HDL cholesterol, there was a split, with a link to a higher risk of heart disease in white participants, not in black participants.

The study is the first to find a difference in risk associated with low levels of HDL cholesterol between black and white men. It also adds to the accumulating evidence that a high level of HDL cholesterol is not necessarily beneficial for heart health.

There are other effects of HDL that can be good. But the researchers also found that HDL’s role in health is complex and ever-changing, with the amount to match the drought.

The link between HDL and heart disease is unclear

Care has long been explained as “good” versus “bad.” A high level of the “good” type has been linked to a lower risk of cardiovascular disease, while having a lot of the “bad” type — through low-density lipoprotein, or LDL, particles — has been linked to a higher risk.

One of the major references to handing HDL cholesterol with the “good” label came from the Framingham Heart Study, a government effort initiated in 1948 to investigate risk factors for cardiovascular disease. In 1977, Framingham researchers reported an inverse relationship between HDL cholesterol and coronary disease risk in a group of white participants.

But later studies concluded that high levels are automatically good for heart health. People with a genetic mutation that boosts their HDL cholesterol level, for example, have no lower risk of heart attack than people without the mutation.SN: 5/18/12). And a class of drugs to raise HDL cholesterol did a great job recruiting numbers, but it didn’t make a difference when it came to cardiovascular risk.

A person’s HDL cholesterol level is only one part of the story, however. Commonly reported on blood tests, the level reports the amount of cholesterol that the HDL particles have on the board. HDL removes cholesterol from the arteries to be excreted by the liver. This helps keep cholesterol from building up on the artery walls, which can eventually impede blood flow.

Recently, HDL research has begun to look beyond its cholesterol payload. “The big understanding over the last decade or so is that while you can measure cholesterol, you can’t really measure the actual functions that HDL does in the body,” says Anand Rohatgi, a cardiologist at Texas Medical University Southwestern. A hundred in Dallas.

How well HDL removes cholesterol, the material appears. One measure of this HDL’s performance is its ability to take up cholesterol from a type of cell called a macrophage. In a US study of nearly 3,000 adults, 49 percent of whom were Black had a higher ability to have a lower incidence of heart attack or stroke, Rohatgi and colleagues reported in New England Journal of Medicine in 2014

Raising the body’s cholesterol is one of HDL’s many jobs. HDL also has anti-inflammatory and other protective effects that appear to protect against cardiovascular disease. But even these effects do not always lead to a good trap. In some circumstances, HDL can become dysfunctional, so that its ability to absorb cholesterol is reduced and it contributes to inflammation. That HDL function can change, depending on the context, was studied to challenge HDL particles, Rohatgi says.

How well HDL performs is still far from something that can be tested as part of a regular physical exam. It’s not clear “what to do yet for the public,” said Nathalie Pamir, a researcher who studies cardiology at Oregon Health & Science University in Portland.

The impact of HDL cholesterol on heart health may differ by gender

While researchers are working toward a more complete understanding of HDL and how to better use it as a clinical measure, the view of HDL cholesterol as uniformly “good” is still unclear. And one level of HDL cholesterol is still an entry in a widely used calculator that assesses cardiovascular risk. Pamir and his colleagues wanted to examine what high and low HDL cholesterol levels mean in today’s diverse population.

In the new study, the team analyzed data from the trial to study potential regional and racial differences in death from stroke in the United States. The study included nearly 24,000 participants — of whom 42 percent were black — who did not start coronary heart disease. Over an average of 10 years, 664 of 10,095 black participants and 951 of 13,806 white participants had a heart attack or died from one.

Increased levels of “bad” LDL cholesterol were linked to a higher risk of coronary heart disease, in line with past research, the team found. But for HDL cholesterol, high levels were not protective at all, and low levels were only predictive of higher risk in white people. What the findings suggest is the need to revisit how HDL cholesterol is used in cardiovascular disease risk calculators, Pamir says.

More than just good, HDL cholesterol is “complex,” he says. If a patient has high HDL cholesterol, the doctor “may say, ‘Well, we don’t know what that means right now.’

Although the study suggests that the impact of HDL cholesterol levels on disease risk differs by gender, it is important to remember that gender is a social construct, not a biological one, says Clyde Yancy, chief of cardiology at Northwestern University Feinberg School of Medicine. at Chicago

Some risk factors for coronary heart disease, including high blood pressure and smoking, “are more prevalent in self-described black Americans,” he says. And community access to health care, nutritious food and education and employment opportunities can affect those at risk.SN: 5/15/17). “There is something unique about the location and the history of the location that can predispose to hypertension, obesity, even diabetes,” Yancy said.

It will take more research to find out what is behind the potential gender-based difference that the study reports, Yancy says, and what it means in terms of HDL cholesterol levels and cardiovascular disease risk. But there remains a chance that high levels of LDL cholesterol — which can accumulate in artery walls — are associated with greater risk, he says. “The LDL cholesterol seems to be our most relevant barometer.”

For all that is known about the factors that impact the risk of cardiovascular disease, researchers still do not have the full picture. More often, cardiologists see heart attack patients with normal cholesterol levels and normal blood pressure, Yancy says, warning that with current methods, “we can’t capture the whole risk.”