Can cholesterol go too low? Study sees cancer link

By Maggie Fox and Ben Hirschler

WASHINGTON/LONDON (Reuters) - Lowering cholesterol as much as possible may reduce the risk of heart disease, but with a price: taking it too low could raise the risk of cancer, U.S. researchers reported on Tuesday.

Patients who took statin drugs to lower their cholesterol had a slightly higher risk of cancer, although the study did not show that the statin drugs themselves caused the cancer.

The researchers found one extra case of cancer per 1,000 patients with the lowest levels of LDL -- low density lipoprotein or so-called bad cholesterol -- when compared to patients with higher LDL levels.

Dr. Richard Karas of Tufts University School of Medicine in Boston and colleagues did not look directly at patients for their study, published in the Journal of the American College of Cardiology.

They did what is known as a meta-analysis, looking at the records of 41,173 patients in 23 different trials of statins.

"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," Karas said in a statement.

Some experts cautioned that the general public could misunderstand the meaning of the study.

"You have to be careful about these things, because people stop taking their statins because they are afraid of cancer and then they die of heart attacks," said statin expert Dr. John LaRosa of the State University of New York Downstate Medical Center in Brooklyn, who wrote a commentary in the journal.

Statins are the world's top-selling drugs, pulling in billions of dollars for their makers. They lower the risk of heart attack and stroke, and evidence also suggests unexpected benefits, such as a lowered risk of death from influenza, pneumonia and the effects of smoking.

Experts believe some of the beneficial effects may come from the drugs' effects on inflammation in the body.

EXTRA-LOW CHOLESTEROL RISKS

But people with extra-low cholesterol may have a higher risk of Parkinson's disease. Statin drugs can also damage the liver and muscles.

The Karas study renews concerns about cancer, as well.

Karas and colleagues examined the records of patients treated with popular statins, including Pfizer Inc.'s Lipitor and Merck & Co. Inc.'s Zocor, now off patent.

They did not include data from recently launched statins such as AstraZeneca Plc's Crestor and Merck/Schering-Plough Corp.'s Vytorin.