Back grey_arrow_rt.gif
Higher HDL Might Lower Cancer Risk
  MedPage Today
Published: June 14, 2010
Action Points
* Explain to interested patients that this study could not determine whether higher HDL actually led to lower cancer risk or was merely a surrogate marker for lower cancer risk.
* Note that lifestyle changes may be recommended for patients with low HDL regardless of any association of HDL with cancer risk.
Break out the niacin! Higher HDL cholesterol levels appear independently linked to lower cancer risk, a meta-analysis found.
The analysis of two dozen randomized, controlled lipid intervention trials found that each 10-mg/dl higher increment of HDL cholesterol was associated with a relative 36% lower risk of incident cancer (95% confidence interval 24% to 47%, P<0.001), according to Richard H. Karas, MD, PhD, of Tufts Medical Center in Boston, and colleagues.
This relationship persisted even after adjusting for baseline LDL cholesterol, age, body mass index (BMI), diabetes, sex, and smoking status, Karas and colleagues reported in the June 22 issue of the Journal of the American College of Cardiology.
Epidemiologic studies have suggested higher risk of incident cancer with lower total cholesterol levels, and a meta-analysis of statin trials by Kara's group showed the same is true for LDL cholesterol levels.
The researchers were quick to note that these association studies cannot prove cause and effect, although HDL may have anti-inflammatory and antioxidant properties that could potentially fight cancer.
There is some evidence for a causal link with HDL cholesterol, noted Jennifer G. Robinson, MD, MPH, of the University of Iowa in Iowa City, in an accompanying editorial.
"However, the most important criteria for causality have not yet been met (lack of alternative explanations and proof by experiment)," she wrote.
Rather, she added, low HDL is likely simply a marker for elevated risk of chronic diseases that "increase inflammation and insulin resistance, which may directly influence atherosclerosis and carcinogenesis."
Regardless of whether high HDL actually lowers cancer risk, recommendations for healthy lifestyle changes -- quit smoking, improve diet, engage in regular physical activity, and control weight -- could particularly benefit patients with low HDL, since making such changes can help prevent many of the chronic diseases associated with aging, she said.
Aside from lifestyle factors, niacin is the most effective agent for boosting HDL -- elevating so-called "good cholesterol" by 20% to 30%. Fibrates can also increase HDL between 10% to 20%. However, statins have little, if any, benefit for raising HDL.
Karas' group analyzed 24 randomized controlled lipid intervention trials with at least 1,000 patient-years of follow-up each for a total of 76,265 intervention-group patients and 69,478 controls followed for a median of five years.
The 8,185 incident cancers appeared significantly linked to HDL cholesterol in the unadjusted analysis, with a 28% lower risk for each 10-mg/dl higher level (P=0.018).
However, the magnitude of the link did not differ between intervention and control groups (P=0.95) or by type of intervention (P=0.726).
After controlling for the other significant factors in cancer risk, the link became even stronger.
The researchers cautioned that the meta-analysis was limited by the available randomized, control trial-level data, a lack of individual patient data, lack of uniform identification of cancers across trials, and follow-up periods that were potentially too short (a median of five years) to see if the associations changed over time.
"These findings underscore the importance of reporting cancer rates in future lipid intervention trials and further support the importance of basic scientific research to determine potential underlying mechanisms that might mediate these associations," they concluded in JACC.
Karas reported having received speaker and consulting fees from Abbott Laboratories and Merck.
A co-author reported being a recipient of a faculty development award from Pfizer/Tufts Medical Center.
Robinson reported that her institution has received grants from Abbott, Aegerion, Bristol-Myers Squibb, Daiichi-Sankyo, GlaxoSmithKline, Hoffman-La Roche, Merck, and Merck Schering-Plough.
Primary source: Journal of the American College of Cardiology
Source reference:
Jafri H, et al "Baseline and on-treatment high-density lipoprotein cholesterol and the risk of cancer in randomized controlled trials of lipid-altering therapy" J Am Coll Cardiol 2010; 55: 2846-54.
Additional source: Journal of the American College of Cardiology
Source reference:
Robinson JG "Low high-density lipoprotein cholesterol and chronic disease risk marker or causal?" J Am Coll Cardiol 2010; 55: 2855-57.
  icon paper stack View Older Articles   Back to Top