It’s likely true that what’s important is not HDL cholesterol levels as measured in conventional lipid panels, but rather HDL function. HDL particles have many beneficial effects: antioxidative, anti-inflammatory, vasodilatory, antiapoptotic, and antithrombotic. A better biomarker – one that reflects these functional benefits – may be cholesterol efflux capacity, as was shown in a recent study by investigators in the Dallas Heart Study (N Engl J Med. 2014; Dec 18;371[25]:2383-93), according to Dr. Genest.
Dr. Christie Ballantyne
Session cochair Dr. Christie Ballantyne was particularly interested in the 2.8% of CANHEART participants with an HDL cholesterol level greater than 90 mg/dL and their associated increased mortality from causes other than cancer and cardiovascular disease.
“I’ve seen similar data once before, in a Russian cohort. Cold weather and alcohol – I wonder if that’s a factor here. The alcohol exposure we saw in the Russian cohort with the 90 HDL levels was really rather striking. And it wasn’t cardiovascular or cancer mortality that they faced, it was other mortality. So I wonder if it’s not an alcohol-related thing, especially in places where you have long, cold winters,” commented Dr. Ballantyne, professor of medicine and of molecular and human genetics at Baylor College of Medicine and director of the Center for Cardiovascular Disease Prevention at the Methodist Debakey Heart Center in Houston.
Dr. Genest was skeptical.
“I think clinicians would argue that seeing an HDL of 90 would be very unusual in a male even if he drinks like an American at a football game,” the Canadian quipped. “ It’s probable that a genetic predisposition plus heavy alcohol is involved.”
Dr. Ko said he and his coinvestigators are scrutinizing the “other deaths” in the very-high HDL cholesterol subgroup, looking for an increase in deaths due to liver cirrhosis, trauma, and other obvious alcohol-related causes. “We haven’t really found a specific pattern,” according to the physician.
Dr. Ballantyne was undeterred. “It may end up being that the person who drinks heavily has some general health issues where trouble occurs because of alcohol in combination with medications rather than a specifically alcohol-related death,” he advised.
The CANHEART study is sponsored by the Canadian Institutes of Health Research. Dr. Ko reported having no financial conflicts of interest.