Triglycerides Found to Be Perilous on Their Own

People who dramatically reduce their “bad” cholesterol still run the risk of heart disease from high levels of fatty acids known as triglycerides, USC researchers say.

High cholesterol has been identified as an artery-clogger and a major contributor to heart attacks. But the role of triglycerides has been a subject of intense debate.

Many doctors do not believe that high triglycerides are a danger in themselves; rather, they believe that triglycerides act in concert with other risk factors, such as high levels of “bad” or low-density lipoprotein cholesterol and low levels of the “good” or high-density lipoprotein cholesterol.

In a study published in the July edition of the American Heart Assn. journal Circulation, a team led by Dr. Howard N. Hodis of USC found that when LDL cholesterol levels were aggressively lowered with the drug lovastatin, triglycerides continued to contribute to the growth of small to moderate-size blockages of vessels leading to the heart.

That finding was based on X-ray imaging that tracked the progression of these blockages, known as plaques or lesions. These blockages can lead to heart attacks.

Hodis, director of the atherosclerosis research unit at the USC School of Medicine, concluded that cholesterol had masked the danger of triglycerides.

“It is difficult to demonstrate the importance of triglycerides until you take the LDL away,” he said.

His study, funded by the National Heart, Lung and Blood Institute, is the first to link triglycerides with the development of smaller lesions, which are considered more dangerous than larger lesions because they’re more likely to rupture and block an artery.

Of 114 patients who took lovastatin, 112 had small and moderate-size lesions to begin with. To evaluate the role of triglycerides, Hodis and his team looked at levels of a protein associated with how the body metabolizes triglycerides.

They found that in the group with the highest levels of that protein, there was a fivefold greater risk of continued lesion growth. Of the 28 people with the highest levels of the protein, 82% had growth and 18% did not.

Hodis said the next step is to see if lowering triglyceride levels and controlling cholesterol with drugs further slows the progression of disease.