Cancer causer?: Lowering your 'bad' cholesterol levels by eating less fatty foods or taking statin drugs has proven benefits, but using drugs to achieve very low levels may be linked to an increased risk of cancer.
Credit: iStockphoto
SYDNEY: Having a low cholesterol rate has been championed as the key to preventing heart disease. But a new study hints at a link between very low LDL cholesterol levels and cancer.
Though recent U.S. guidelines have advocated increasingly high doses of statin drugs to lower levels of LDL or 'bad' cholesterol and prevent heart disease, the new study indicates that there may be a risk for patients taking the highest doses.
Low-density lipoprotein (LDL) cholesterol can clog up arteries with plaques that lead to heart attacks and strokes. Statins, a class of enzyme inhibitors that work in the liver, lower LDL cholesterol levels by clearing it from the bloodstream.
Chance finding
U.S. researchers analysed 23 existing studies of statin drugs – covering over 41,000 patients – in an effort to detect side effects of the drugs; such as whether they damage liver or muscle cells. Though statins have proven benefits against heart disease, they also cause side effects, with particular damage to liver and muscle cells.
By chance the researchers found that patients with very low levels of LDL cholesterol had one further incidence of cancer per 1000 patients, than patients with higher levels. The findings are published in the current issue of the Journal of the American College of Cardiology.
"This analysis doesn't implicate the statin in the increasing risk of cancer," said lead author Richard Karas at Tufts University School of Medicine in Boston, Massachusetts. "The demonstrated benefits of statins in lowering the risk of heart disease remain clear; however certain aspects of lowering LDL with statins remain controversial and merit further research."
Further research is needed to determine if the slight increased cancer risk is a side effect of the statin drugs themselves or is linked to the low LDL cholesterol levels, said Karas.
"Significant benefit"
"These current findings provide insufficient evidence that there is any problem with LDL lowering that outweighs its significant benefit on vascular disease," commented statins expert John LaRosa of the State University of New York, who wrote an accompanying editorial in the same journal. However, "we must continue to be vigilant in ensuring that its benefits clearly outweighs its risks," he said.
The results "raise important questions" but a causal relationship with statins cannot be confirmed without additional research, added James Dove, president of the American College of Cardiology in Washington DC.
The low levels of bad cholesterol linked to cancer in the study were achieved with statin drugs and were below levels that could be achieved by limiting bad cholesterol in the diet alone.
