The link between HDL and heart disease isn't clear-cut:
"Good" and "bad" cholesterol: These well-known characters have long starred in the saga of heart health. But in a major plot twist, "good" cholesterol, it turns out, is not always so 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 conflicted story about HDL's effect on cardiovascular disease.
And a new, large study brings fresh doubt. High levels of HDL cholesterol were not associated with protection against heart disease in Black or white participants, researchers reported in the November Journal of the American College of Cardiology. For low levels of HDL cholesterol, there was a split, with a link to higher risk of heart disease in white participants but not in Black participants.
The study is the first to find a difference in the risk tied to low levels of HDL cholesterol between Black and white people. It also adds to accumulating evidence that a high level of HDL cholesterol isn't necessarily helpful for one's heart health.
There appear to be other attributes of HDL that can be good. But researchers have also found that HDL's role in health is complicated and ever-changing, with plenty to figure out.
Cholesterol has long been explained as the "good" versus the "bad." A high level of the "good" kind has been tied to a lower risk of cardiovascular disease, while having lots of the "bad" kind — carried by low-density lipoprotein, or LDL, particles — has been linked to a higher risk.
[...] A person's HDL cholesterol level is just one part of the story, though. Commonly reported on blood tests, the level reflects the amount of cholesterol that HDL particles have on board. HDL carries cholesterol away from the arteries to the liver to be excreted. This helps keep cholesterol from building up in artery walls, which can eventually impede blood flow.
Recently, research on HDL has started looking beyond its cholesterol payload. "The big understanding over the last decade or so is that while you can measure the cholesterol, it doesn't really reflect the actual functions that HDL is doing in the body," says Anand Rohatgi, a cardiologist at the University of Texas Southwestern Medical Center in Dallas.
How well HDL removes cholesterol appears to matter. One measure of this job performance is HDL's ability to receive cholesterol from a type of cell called a macrophage. In a U.S. study of close to 3,000 adults, 49 percent who were Black, the higher this capacity, the lower the incidence of heart attacks or strokes, Rohatgi and colleagues reported in the New England Journal of Medicine in 2014.
Ridding the body of cholesterol is just one of HDL's many jobs. HDL also has anti-inflammatory and other protective effects that appear to guard against cardiovascular disease. But even these effects don't always lead to a net good. In certain circumstances, HDL can become dysfunctional, such that its capacity to receive cholesterol is reduced, and it contributes to inflammation. The fact that HDL's roles can change, depending on the context, has made studying HDL particles challenging, 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 "how to do it yet for the general public," says Nathalie Pamir, a researcher who studies cardiology at the Oregon Health & Science University in Portland.
As researchers work toward a fuller understanding of HDL and how it might be better used as a clinical measure, the view of HDL cholesterol as uniformly "good" is still out there. And one's HDL cholesterol level is still one entry in a widely used calculator that estimates cardiovascular risk. Pamir and her colleagues wanted to examine what high and low HDL cholesterol levels mean in a contemporary, diverse population.
[...] For all that is known about what impacts cardiovascular disease risk, researchers still don't have the full picture. The number of times that cardiologists see heart attacks in patients with normal cholesterol levels and normal blood pressure, Yancy says, suggests that, with current methods, "we're not able to capture the entirety of the risk."
Journal Reference:
Race-Dependent Association of High-Density Lipoprotein Cholesterol Levels With Incident Coronary Artery Disease, Journal of the American College of Cardiology (DOI: https://www.jacc.org/doi/10.1016/j.jacc.2022.09.027)
(Score: 1) by TaxiCabJesus on Saturday January 14, @05:16AM (1 child)
I bet someone already figured out what's important about cholesterol - humans are constantly rediscovering what previous generations had already figured out. I have a friend who says her mother did not do well with the liver poison she was prescribed to lower her cholesterol levels.
(Score: 2) by Mojibake Tengu on Saturday January 14, @07:23AM
Hint: look at what the brain is built from.
The edge of 太玄 cannot be defined, for it is beyond every aspect of design