Your favorite news website, the 11:00 PM news, the hourly reports on your local radio station - chances are that when medical breakthroughs make the news, you hear about them repeatedly on all channels. But lots of attention in the news media or frequent citations in scientific journals doesn't automatically mean that medical research is correct or accurate, says a researcher from Tufts-New England Medical Center in Boston, Massachusetts.
He examined clinical research studies that had been cited in the medical literature at least 1,000 times. The original articles were published between 1990 and 2003 in some of the most prominent medical journals, including the New England Journal of Medicine, Journal of the American Medical Association, and The Lancet. For each study, the author checked for additional studies to find out how often the original study was contradicted or found to have a lesser effect than first reported.
Out of the 49 eligible highly cited studies, 45 said that the medical intervention - whether it was a medication, surgical procedure, or type of therapy - proved effective. But later research contradicted seven (or 16%) of these studies and reported weaker effects for another 16%. Here's one example: In 1991, a study in the New England Journal of Medicine reported that women who took hormone therapy for menopause symptoms had a 44% reduction in coronary artery disease. A larger study published later refuted those results and showed that taking hormones actually increased the risk of heart problems in postmenopausal women.
Overall, about a third of the study results didn't hold up against future research, although the author points out that this does not necessarily mean that the original study was totally wrong or that later studies, even if larger and better designed, are completely right.
What This Means to You: When you're reading recent health headlines, keep in mind that one study doesn't necessarily provide the whole picture. Just because a study receives lots of media attention doesn't mean it's the final word on the subject. Although the findings from medical journals can help parents learn a lot about new medical treatments, including ones that may have an affect on children's health to get the complete medical perspective, you should discuss them with your child's doctor. He or she can interpret the medical studies and help you understand whether they apply to your child's health and medical condition.
Source: John P. A. Ioannidis, MD; Journal of the American Medical Association, July 13, 2005
Reviewed by: Mary L. Gavin, MD
Date reviewed: August 2005
