Taking a cholesterol-lowering statin will lower your cholesterol but it won't cut your risk of developing colorectal cancer, according to study of more than 400,000 Canadians.

Our study suggests that there is no significant reduction in the risk of colon cancer with regular use of statins, irrespective of the dose or duration of statin use, lead investigator Dr. Harminder Singh of the University of Manitoba in Winnipeg told Reuters Health.

Colorectal cancer is the third most common cancer worldwide, and effective preventive agents would have important implications for public health.

Although laboratory studies have indicated that statins -- which include drugs such as Lipitor, Crestor, Pravachol, and Mevacor -- can inhibit cancer cell progression, clinical trials have failed to confirm these findings.

To investigate further, Singh's team turned to Manitoba's province-wide prescription drug database. They identified 35,739 middle-aged adults who were regular statin users, including 10,287 who had been taking statins for at least 5 years (long-term users), as well as 377,532 similarly aged adults with no record of a prescription for statins.

The median follow-up was 3 years for the regular users (starting from the date of their first prescription) and 7 years for long-term users (starting after 5 years of statin therapy).

Regular use of a statin did not curb the risk of colorectal cancer, the investigators report in the American Journal of Gastroenterology.

This study did not find any statistically significant reduction in colorectal cancer risk with regular use of statins, irrespective of the dose or duration, they wrote.

In a commentary, Dr. Dennis J. Ahnen and Dr. Tim Byers of the University of Colorado, Denver agree with the researchers' conclusions.

They write, The best-designed studies of the issue indicate that statin use is neither a major risk factor nor a protective factor for colorectal cancer and that we have come very near to the end of the road for the hypothesis relating statins to colorectal cancer risk.

SOURCE: American Journal of Gastroenterology, December 2009.

Cancer