September 25 (HealthDay News) -- Statins, taken by millions to lower cholesterol, may hinder the body's ability to repair muscles, University of Alabama researchers report.

The most frequently reported side effect of statin therapy is fatigue, with about 9 percent of patients reporting muscle pain. As doses of the medication are increased, and physical activity is added, these effects can be more pronounced. These side effects are found in all commonly used statins.

"While these are preliminary data and more research is necessary, the results indicate serious adverse effects of statins that may alter the ability of skeletal muscle to repair and regenerate due to the anti-proliferative effects of statins," lead researcher Anna Thalacker-Mercer said in a statement.

Results of the study were presented Thursday at a meeting of the American Physiological Society, in Hilton Head, S.C.

For the study, Thalacker-Mercer's team exposed muscle cells to varying doses of simvastatin.

The researchers found as the dosage increased, the ability of these cells to multiply decreased. For the equivalent of 40 milligrams a day, growth of new muscle cells was reduced by 50 percent.

When doses were increased, proliferation of these cells continued to decline to the point where they could have a negative affect on the ability of muscles to heal and repair themselves, the researchers found.

"We are very interested in these effects in the older population," Thalacker-Mercer said. "It is possible that older adults may not be able to distinguish between muscle pain related to a statin effect or an effect of aging, and therefore adverse effects of statins in older adults may be under-reported. Therefore, our next step is to examine statins among older adults," she said.

Dr. Gregg C. Fonarow, a professor of cardiology at the University of California, Los Angeles, thinks that this research may lead to ways of preventing muscle damage in patients taking statins.

"Statins are among the most extensively studied medications and provide cardiovascular benefits that greatly outweigh potential risks in most patients," Fonarow stressed.

Between 2 percent and 8 percent of patients report having muscle aches in response to statins, Fonarow noted. "Significant muscle damage as result of statin treatment rarely occurs, but if it does, there can be serious consequences," he noted.

This study suggests that high doses of a statin may alter the ability of skeletal muscle cells to repair and regenerate, Fonarow said. "This research may eventually lead to new ways to minimize or prevent statin-induced muscle damage," he added.

SOURCES: Gregg C. Fonarow, M.D., professor, cardiology, University of California, Los Angeles; Sept. 25, 2008, presentation, American Physiological Society meeting, Hilton Head, S.C.