Background Statins are cholesterol lowering drugs that are prescribed to lower the risk of cardio-vascular diseases. The use of statins has increased markedly and it is now one of the most prescribed drugs in the world. 600,000 people in Denmark are taking statins on a daily basis, 40 % of these are taking the medication without having any other risk factors for cardio-vascular diseases than elevated blood-cholesterol i.e. they are in primary prevention.