A recently published meta-analysis of 13 randomized controlled trials that included a total of 91,140 participants found that treatment with cholesterol-lowering statin drugs signficantly increased the risk of developing diabetes....
The increase in diabetes incidence of this new study was relatively small (9% compared with placebo), and 255 patients had to be treated with a statin drug for four years to cause one new case of diabetes. However, the benefits of statin drugs are relatively small. In one study, for example, 100 patients had to be treated with a statin drug for an average of 3 years in order to prevent one heart attack. Thus, for every heart attack prevented by a statin, approximately 30 new cases of diabetes will occur. Considering that one of the major long-term complications of diabetes is heart disease, and considering that most statin trials have lasted only several years, the results of the new meta analysis suggest that the cardioprotective effect of statin drugs will begin to wane with time. That possibility is not encouraging because many patients prescribed statins are relatively young and are expected to stay on the treatment indefinitely.
He goes on to theorize that the effect is probably due to less vitamin D caused by lower cholesterol levels.