You can’t always believe what you read, study finds

The news from the health front is always marching on – that’s the trouble. It’s so hard to keep up with. Just when you think you know what’s good for you, along comes a study to prove you don’t.

There might be a good reason for that.

Recently, the Journal of the American Medical Association published a review of 49 prominent medical studies – ranging from using vitamin E and beta carotene to fight lung cancer to the difference between using stents and balloon angioplasty to combat cardiovascular disease – that found nearly a third were later completely contradicted or had a smaller effect than first reported.

We all know the scenario. A small study comes out in a respected medical journal saying that a particular treatment is just what the doctor ordered. Headlines play up the story in bigger venues everybody reads. There is much happiness, and life goes on. Until another researcher comes along and says, hey, the sample was too small and refutes the conclusions that drew all the publicity. But maybe that news doesn’t have legs so you never hear it.

The question is whether some studies are more likely to be contradicted later. And the short answer is yes.

The researcher who published this meta-analysis is Dr. John Ioannidis, a clinical epidemiologist at the University of Ioannina School of Medicine in Greece. Because clinical research is so time-consuming, he advises that results, “no matter how impressive, should be interpreted with caution, when only one trial is available.”

That’s small comfort, indeed.