Evidence for medical treatments, like Campbell’s soup, comes in many different varieties. As Dr Malcolm Kendrick’s latest feature reveals, when evidence is needed to licence the first post-statin drug intended to cut the risk of a heart attack, there is no need to show it actually does cut the risk, only that is lowers cholesterol, which is not necessarily the same thing at all.
Contrast that with the quality of evidence required before permitting large scale treatment of the serious vitamin D deficiency that affects a large proportion of the population of the UK. Rufus Greenbaum has been investigating the little known government committee that is responsible for advising on supplementation. Its chairman explained it wasn’t concerned with how vitamin D might improve health, only with managing the risk it poses.