Challenging "good" cholesterol’s role in heart health

For decades people were told that high-density lipoprotein (HDL) was “healthy” and low-density lipoprotein (LDL) was “lousy.” Research by Dr. Dennis Ko, a scientist in the Schulich Heart Research Program at Sunnybrook Research Institute calls this binary doctrine into question.

He has shown that high levels of HDL do not protect against cardiovascular disease. In a study published in the Journal of the American College of Cardiology, he examined the HDL cholesterol levels and outcomes of more than 600,000 people in Ontario aged between 40 and 105 years. Following up this group four years after the study started, the researchers analyzed deaths from cardiovascular diseases, cancer and other causes. People with lower HDL were at higher risk of death from both cardiovascular and noncardiovascular conditions. If HDL were truly a marker for cardiovascular health, then it shouldn’t be implicated in other causes of death, the researchers reasoned. That wasn’t the case. Moreover, people with the lowest and highest levels of HDL cholesterol had a higher overall risk of death from all causes than those whose HDL cholesterol levels were average.

The study was named the fifth most influential paper of more than 1,000 papers published in 2016 by the journal, which is top-ranked in cardiology.