HDL cholesterol–cancer link bolstered
MedWire News: Meta-analysis findings support a possible effect of low levels of high-density lipoprotein (HDL) cholesterol on the risk for cancer.
The study, published in the Journal of the American College of Cardiology, included 24 randomized controlled trials involving 76,265 patients allocated to lipid-modifying interventions (mainly statins) and 69,478 given a control intervention.
Patients in these studies developed a total of 8185 cancers, report Richard Karas (Tufts Medical Center, Boston, Massachusetts, USA) and colleagues.
The patients’ cancer risk was inversely linked to HDL cholesterol levels, such that each 10-mg/dl increase in baseline HDL cholesterol was associated with a 36% reduction in the risk for developing cancer.
The association was independent of baseline low-density lipoprotein (LDL) cholesterol levels, age, body mass index, diabetes, gender, and smoking status.
LDL cholesterol levels were also inversely associated with cancer risk, but other studies have shown this to be reverse causality, ie, low LDL cholesterol levels do not precede the development of cancer.
The relationship between baseline HDL cholesterol and cancer risk was also shown in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) study, as reported by MedWire News. In this study, the relationship persisted for cancers that developed more than 12 years after study entry.
In an accompanying editorial, Jennifer Robinson (University of Iowa, Iowa City, USA) said: “Evidence of causality would suggest that interventions to increase HDL cholesterol could decrease the risk for the two most important causes of morbidity and mortality in the USA.”
She said that the relationship between HDL cholesterol and cancer risk fulfills several criteria for causality, including low levels predating cancer, evidence for a dose response, and biologic plausibility.
However, Robinson stressed that the relationship has not yet met the two most important criteria: exclusion of alternative explanations and supporting evidence from randomized trials.
“At this time, the evidence best supports low HDL cholesterol as a marker for an overall increased risk for chronic disease,” she concluded.
But she added: “Regardless of the effects on HDL cholesterol, healthy lifestyle habits have a significant impact on the prevention of most of the chronic diseases associated with aging.”
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By Eleanor McDermid