Statin, a type of drug used to lower a person's cholesterol level, may have some beneficial effects but many people stopped using the drug or avoided it because of its perceived side effects. Findings of a new study, however, show that some of the side effects associated with the cholesterol pill are not caused by it.

Statin has been linked to myopathy, fatigue, muscle aches and rhabdomyolysis but researchers of a new study that looked at 29 randomized controlled trials that compared statin to placebo and involved more than 80,000 patients found that many of these side effects do not occur more in patients taking the cholesterol-lowering drug than those taking placebo.

"It surprised me," said  study author Darrel Francis, a professor of cardiology at the National Heart and Lung Institute at Imperial College London. "You would think that if statins were causing lots of muscle aches, there would be less in people taking placebo. But it doesn't actually increase."

Reporting their findings in "What proportion of symptomatic side effects in patients taking statins are genuinely caused by the drug? Systematic review of randomized placebo-controlled trials to aid individual patient choice", which was published in the European Journal of Preventive Cardiology March 12, the researchers said that the only harmful side effect they found associated with statin is diabetes. Only 2.4 percent of individuals taking placebo get newly diagnosed diabetes mellitus, which is lower when compared with 3 percent in those taking statin.

"Only a small minority of symptoms reported on statins are genuinely due to the statins: almost all would occur just as frequently on placebo," the researchers wrote. "Only development of new-onset diabetes mellitus was significantly higher on statins than placebo; nevertheless only 1 in 5 of new cases were actually caused by statins."

The researchers also noted that statin also cause a slight increase in liver enzymes although it isn't clear if this has harmful effects. "Higher statin doses produce a detectable effect, but even still the proportion attributable to statins is variable: for asymptomatic liver enzyme elevation, the majority are attributable to the higher dose; in contrast for muscle aches, the majority are not," the researchers reported.

The researchers, however, said that their analyses may not actually reflect real-life clinical experience as individuals who participate in clinical trials may differ from real-life patients and different trials vary in how they search for and document side effects. Some side effects associated with statin including memory problems, blurred vision, ringing in the ears and skin problems were not also covered in the study.