Heart disease is the leading cause of death in the United States, killing hundreds of thousands of people each year, and cholesterol levels are widely known as one of the biggest risk factors predicting heart attacks. Current guidelines and advice emphasize lowering LDL, the so-called “bad” cholesterol, as the primary goal in reducing cardiovascular risk, but Indiana University Chancellor's Professor of Medicine William Tierney says that's not enough.

Tierney and scientists from the IU School of Medicine's Regenstrief Institute and from the pharmaceutical company GlaxoSmithKline, Inc. (who funded the research) studied nearly 7,000 patients from a large urban area; the group included large numbers of African Americans, women, smokers, and people who had diabetes or hypertension. According to the study, published in the American Heart Journal , the researchers discovered that patients with high HDL, or “good” cholesterol, had significantly lower cardiac risk. In other words, when it comes to lowering risk of heart attacks, having more “good” HDL cholesterol is more important than having less “bad” LDL cholesterol.

“Having a high total cholesterol reading may not be bad,” says Tierney. “In fact, it may be good if it is the HDL component that is high. Conversely, a low total cholesterol reading is not necessarily good because it can hide a low HDL level.”

The study was repeated focusing on stroke as the outcome, rather than heart disease, and the results were the same: HDL cholesterol was a strong predictor of stroke, and LDL cholesterol was not.

As a result of their work, Tierney and his colleagues encourage physicians to pay closer attention to HDL as a predictor of cardiovascular disease.

Co-authors on the study included Timothy Stump, a statistician at the Regenstrief Institute Inc, an internationally recognized health-care research organization.