Heart Health: What Your Cholesterol Level Doesn’t Tell You

If you see your doctor for a routine physical, chances are they’ll take your blood pressure, do a physical exam and draw some blood to send for testing. One of those tests will likely be a lipid panel. A lipid panel measures the lipids in your blood to make sure they’re within a healthy range. A standard lipid panel checks your LDL-cholesterol, HDL-cholesterol and triglyceride level. LDL-cholesterol is a form of cholesterol linked with heart disease while a higher HDL-cholesterol may be protective. What about triglycerides? A high triglyceride level is a risk factor for heart disease too. It’s important to know your lipid levels – but are you getting all the information you need from a standard lipid panel?

Cholesterol Testing and Heart Disease Risk

Everyone needs to know their risk factors for heart disease. After all, heart disease is the number one cause of mortality. Lipid abnormalities, including high LDL-cholesterol, low HDL-cholesterol, and high triglycerides, are known risk factors for heart disease. Other risk factors include high blood sugar, high blood pressure, smoking, obesity, and a sedentary lifestyle. Genetics, age, and gender are factors you can’t control but a number of risk factors respond to lifestyle changes. Some research even shows a healthy lifestyle can change the expression of your genes. Men are at higher risk for heart disease, but women and men have a similar risk once women reach the age of menopause. So, heart health is a concern for everyone!

LDL Particle Size: Why It’s Important

There are some things a standard lipid panel doesn’t measure. Although a standard lipid panel gives you a total value for LDL-cholesterol, it doesn’t tell you about the size of the LDL-cholesterol particles you have floating around in your bloodstream. Why is this important? Some LDL particles are light, fluffy and large in size. Others are small and compact. It’s the small, dense LDL particles that of the greatest concern. Small, dense particles can easily lodge inside the walls of arteries and damage them. In addition, these denser particles are more easily oxidized. When small dense particles are oxidized, inflammation and vessel wall damage takes place, damaging the wall of the blood vessel.

Why is damage to the blood vessel wall a problem? Once it’s damaged, plaque can form more easily. As plaque builds up, it can eventually rupture and form a blood clot, leading to blockage of the vessel. When a vessel that supplies the heart is blocked, the heart can’t get enough blood flow and a heart attack results. The whole process may take many years to happen, but why wait until it does?

Limitations of Standard Lipid Testing

When you receive the results of your lipid profile, you get a number showing the total number of LDL particles in your bloodstream. A standard profile doesn’t break the results down into small, dense particles (the most dangerous ones) and light, fluffy particles (the less concerning ones). Some people have a predominance of one kind over the other. If you have a high proportion of small, dense particles your heart disease risk, based on the results of your lipid test, is higher. If you have other risk factors for heart disease like high blood pressure or type 2 diabetes, your risk may be many times higher than the average population.

Is there a way to determine your ratio of small, dense particles to light, fluffy ones? A test called the vertical auto profile test (VAP) test measures particle density and tells you the ratio of small, dense and light, fluffy particles of LDL you have. It costs more than a standard lipid profile but may be worth the extra cost for some people. Doctors still aren’t in agreement about who needs a test like the vertical auto profile test. Some cardiologists believe everyone should get one while others think standard lipid testing is enough.

Who’s a Good Candidate?

Where advanced lipid testing like the VAP would likely be most beneficial is if you have a normal lipid panel, but a family history of heart disease or if you have type-2 diabetes or metabolic syndrome.  Insulin resistance is associated with a higher ratio of small, dense particles even when total LDL-cholesterol is normal. A standard lipid panel may show your total LDL is normal but you have a high proportion of small, dense particles that put you at greater risk for heart disease. In this case, you would want to be more aggressive at lowering your heart disease risk. Without more advanced testing, you would be unaware you have an unhealthy lipid profile.

Another test called the lipoprotein particle profile test is another option that tests LDL particle size. It has the advantage of also measuring remnant lipoprotein. Remnant lipoprotein, or RLP, is believed to be a marker for a higher risk for heart disease. A number of other tests are available that measure LDL particle size. Talk to your doctor about the options.

The Bottom Line?

Standard lipid testing for LDL-cholesterol, HDL-cholesterol, and triglycerides, is helpful but doesn’t always tell the full story. The results of a standard lipid panel may not be representative of your risk for heart disease and stroke. If you have a family history of heart disease or are at high risk for other reasons like type 2 diabetes, talk to your doctor about measuring LDL particle size using a test like the VAP. Just as importantly, lower your risk in other ways by treating high blood pressure, exercising regularly, sitting less, eating a clean, unprocessed diet, checking your blood sugar regularly, getting 7 to 8 hours of sleep a night and keeping your weight under control.

Heart disease is very much a “lifestyle disease.” Make sure you’re leading a heart-healthy lifestyle as much as possible.

 

References:

World Heart Federation. “Cardiovascular disease risk factors”

CDPHP Medical Messenger. “Beyond Routine Cholesterol Testing: The Role of LDL Particle Size Assessment. 2004.

J Am Coll Cardiol. 2013 Jan 29;61(4):427-36. doi: 10.1016/j.jacc.2012.08.1026. Epub 2012 Dec 19.

John Hopkins Medicine. “The New Blood Lipid Tests – Sizing Up LDL-Cholesterol”

Cardiac Biomarkers. “Remnant Lipoproteins and Atherosclerotic Disease”

 

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