CardioExchange Archive

Jaffri and colleagues found a significant inverse association between HDL and the risk of cancer in a meta-analysis of 24 trials that included more than 600,000 person-years of follow-up and 8,185 cancer cases. In their paper in the Journal of the American College of Cardiology, they report a dose-response relationship in which each 10-mg/dl increase in HDL was associated with a 36% lower rate of cancer. The association remained significant after adjustment for other baseline factors, including LDL, age, BMI, diabetes, sex, and smoking status.

“This finding is important because it builds on previous studies demonstrating that low levels of LDL or bad cholesterol and total cholesterol are associated with increased rates of cancer,” said Richard Karas, the senior author of the study, in a press release from the ACC.

In an accompanying editorial comment, Jennifer Robinson discusses the strengths and weaknesses of the finding. Among the strengths she cites the lack of evidence for reverse causality (in which cancer would be the cause of the low HDL levels), the dose-response relationship, and a biologically plausible explanation for the association. On the other hand, she cites several alternate explanations, in which low HDL might be “simply a marker for smoking, obesity, inflammation, or hyperinsulinemia” or other dietary and lifestyle factors. She also observes that “currently there is insufficient evidence to conclude that pharmacologically increasing HDL-C per se reduces cardiovascular events.”

Although “the most important criteria for causality have not yet been met,” Robinson writes in her conclusion:

“Clearly, individuals with low HDL-C may experience particular benefit from lifestyle recommendations to quit smoking, improve diet, engage in regular physical activity, and control weight. Regardless of the effects on HDL-C, healthy lifestyle habits have a significant impact on the prevention of most of the chronic diseases associated with aging.”