Very Low LDL May Mean More Cancer Risk
Risk Found in People Taking Statin Drugs; More Study Needed, Researchers Say
(Editor's note: In August 2008, the researchers announced that
a more complete analysis of the data showed no link between statins and
July 23, 2007 -- New research suggests a link between very low cholesterol
levels and an increased risk of cancer, but the findings are far from
conclusive, researchers say.
The analysis of studies examining outcomes in patients taking
cholesterol-lowering drugs called statins to lower their low density
lipoprotein (LDL) "bad" cholesterol found an elevated risk of cancer
among those who achieved the very lowest LDL cholesterol levels while taking
The findings do not directly implicate statins in increasing cancer risk,
but they do raise important questions, which need to be answered in future
clinical trials, researcher Richard H. Karas, MD, of Boston’s Tufts-New England
Medical Center, tells WebMD.
Statins like Lipitor, Pravachol, Crestor, and Zocor lower LDL levels by
blocking a key enzyme in the liver responsible for making cholesterol.
“Our findings should not be seen as a reason to change clinical practice,”
Karas says. “No one who needs these drugs should stop taking them based on
Is Lower Always Better?
Millions of American take statins to lower their risk of heart attack and
stroke, and in recent years an increasing number have been placed on high doses
of the drugs to achieve lower LDL levels.
The “lower is better” strategy for controlling LDL has been shown to reduce
cardiovascular risk, especially in very high-risk heart patients. But questions
remain about the long-term safety of high-dose statin use.
Karas and colleagues did not have cancer in mind when they set out to
examine the safety of the strategy. They were more focused on two more widely
suspected side effects of statins -- muscle damage and elevated liver
They found no link between very low LDL levels and either of these side
effects, but a clear association was seen between statin use in high doses and
“There was an important and significant relationship between the dose of
statins given and the risk of liver toxicity,” Karas says. “I think this paper
establishes that point quite strongly.”
The analysis failed to show a similar link between statin dosage and muscle
damage. It has long been suggested that in high doses statins raise the risk of
a rare but potentially life-threatening muscle disorder known as
No evidence of a link was found by Karas and colleagues, but the researcher
says there were too few cases of the disorder to prove or disprove the
Karas favors using moderate doses of statins in combination with other
cholesterol-lowering drugs instead of high doses of statins to lower the risk
to the liver.
"To be clear, the benefits of statins far outweigh the risks,” he