A New Way to Measure Cholesterol: Particle Size Indicates Risk

Wednesday, May 04, 2011

ROCHESTER, Minn. — There's a new way to measure the risk of heart disease and stroke: the size of low density lipoprotein, also known as LDL or "bad" cholesterol, particles. The May issue of Mayo Clinic Health Letter explains how smaller particles may increase the risk of heart problems and what can be done about it.

Elevated LDL cholesterol is a major risk in narrowing, hardening or clogging of arteries, which can lead to heart attack, stroke or other forms of heart disease. LDL does its damage by penetrating the inner lining of artery cells. Smaller LDL particles appear to do more damage. When LDL particles are small, heightened risk remains even when overall LDL counts are at ideal levels.

The size of LDL particles can be measured indirectly, by a count of the number of LDL particles in the bloodstream. Higher counts indicate smaller particles. The number can be measured with a test called nuclear magnetic resonance. This test, a follow-up to the standard cholesterol blood test, isn't widely available.

Even without this test, there are several strong indicators of higher risk of heart attack or stroke. High triglyceride levels (150 mg/dL or higher) and low high-density lipoprotein (HDL or "good") cholesterol are associated with large numbers of LDL particles in the blood. So are high blood sugar levels, diabetes and being inactive, overweight or obese and eating a diet high in saturated fat and cholesterol.

The best way to reduce the amount of small-particle LDL is by improving diet, becoming active and maintaining a healthy weight. In addition, medications can help reduce small-particle LDL. Options are prescription niacin (Niaspan) and a class of medications called fibrates. These include fenofibrate (Lofibra, Tricor, others) and gemfibrozil (Lopid).

Mayo Clinic Health Letter is an eight-page monthly newsletter of reliable, accurate and practical information on today's health and medical news. To subscribe, please call 800-333-9037 (toll-free), extension 9771, or visit Mayo Clinic Health Letter Online.

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