You may not recall every lab value from your last physical, but you probably remember one: Your cholesterol level.

If it’s higher than ideal, you’re not alone. According to the U.S. Centers for Disease Control and Prevention, between 2015 and 2018, almost 12% of U.S. adults ages 20 and up had high total cholesterol, defined as above 240 mg/dL. The type that physicians mostly worry about is LDL (or “bad”) cholesterol, which is one component of that total.

The myth: Cholesterol is always harmful.
The facts: Cholesterol, which is often described as a fat-like, waxy substance, is essential to the human body, including playing a key role during fetal development. It’s part of cell membranes and prompts production of crucial hormones. But too much can cause problems, namely contributing to clogged arteries and raising the risk of heart problems. When physicians and researchers talk about cholesterol’s harms, they’re usually referring specifically to low-density lipoprotein. LDL transports cholesterol around the body, depositing it in blood vessels, explains Nathalie Pamir, an associate professor in preventive cardiology at the Oregon Health & Science University in Portland. Its smaller cousin, high-density lipoprotein (HDL), has long been thought of as the “good” cholesterol because it typically ferries cholesterol away from other parts of the body to the liver.

The myth: ‘Good’ cholesterol is always protective.
The facts: The story has gotten more complicated. LDL is still considered to be a bad actor: “Based on current research, there is no level where having it really low is dangerous,” says Dr. Leslie Cho, section head of preventive cardiology and rehabilitation at the Cleveland Clinic. In fact, people with heart disease should aim for less than 70 mg/dL, and people with diabetes and those at very high risk of coronary artery disease are advised to aim for less than 55 mg/dL, she says.

But the HDL story is more complex. Trials of experimental drugs for increasing HDL have not actually reduced heart events, and research has cast doubt on the idea that the higher the HDL levels, the better. Pamir and colleagues published a study in November in the Journal of the American College of Cardiology that followed nearly 24,000 adults without heart disease over about a decade to measure biomarkers and track heart attacks and heart attack-related deaths. While LDL, as well as another form of lipid, triglycerides, “modestly predicted” risk in white and Black adults, low HDL levels were associated with increased risk only in white adults. And high levels of HDL weren’t protective for either white or Black adults.
One potential explanation, Pamir says, is that the quality of the HDL’s functioning may matter more than the sheer quantity. There’s some evidence that high levels may indicate harmful inflammation, Wright adds. And excessive alcohol use or metabolic disorders may lead to higher HDL levels but not to better health. For now, there’s no test for the quality of HDL. Research into the intricacies of HDL by Pamir and others continues. Until there are more definitive answers, it’s important for people with high levels of HDL not to assume it will protect them from heart problems, to take the lifestyle steps that are known to improve heart health, and to talk with their physicians about medication if other factors suggest a higher heart disease risk, cardiologists say.

The myth: You don’t need to get your cholesterol checked until you reach the average age for heart attacks.
The facts: Recommendations vary on when to start, but the AHA recommends that all low-risk adults ages 20 and older have their levels checked every four to six years. Screening will likely be more frequent if you have a family history or a personal history of heart disease. And the American Academy of Pediatrics recommends all children be screened for high cholesterol between the ages of 9 and 11—earlier if they have risk factors like a family history of early heart disease.

Cholesterol is measured using a blood draw. According to guidelines published in 2016, it’s usually not necessary to fast before your test. (Ask your doctor ahead of time to make sure.)

Tarikh Input: 07/11/2023 | Kemaskini: 14/12/2023 | aslamiah