From an article about the wonderful Dr. John Ioannidis of the above title in The Atlantic (my bolds):
In poring over medical journals, he was struck by how many findings of all types were refuted by later findings. Of course, medical-science “never minds” are hardly secret. And they sometimes make headlines, as when in recent years large studies or growing consensuses of researchers concluded that mammograms, colonoscopies, and PSA tests are far less useful cancer-detection tools than we had been told; or when widely prescribed antidepressants such as Prozac, Zoloft, and Paxil were revealed to be no more effective than a placebo for most cases of depression; or when we learned that staying out of the sun entirely can actually increase cancer risks; or when we were told that the advice to drink lots of water during intense exercise was potentially fatal; or when, last April, we were informed that taking fish oil, exercising, and doing puzzles doesn’t really help fend off Alzheimer’s disease, as long claimed. Peer-reviewed studies have come to opposite conclusions on whether using cell phones can cause brain cancer, whether sleeping more than eight hours a night is healthful or dangerous, whether taking aspirin every day is more likely to save your life or cut it short, and whether routine angioplasty works better than pills to unclog heart arteries.
But beyond the headlines, Ioannidis was shocked at the range and reach of the reversals he was seeing in everyday medical research.
Clinical research always must be taken with a grain of salt, and today's "best practices" will be tomorrow's worst. The general press is utterly incompetent at evaluating such studies. I think they just grab at potential headlines, eg Study: Broccoli Cures Causes Cancer.
I know plenty of folks who have been told to "Take it - studies say it might help, and won't hurt." Who knows? I find it amusing to think that today we are no longer certain of a direct relationship between cholesterol levels and heart disease.
