We now get much of our scientific and medical information from the news media. But when the newspaper headlines or the lead television story declare a startling new finding that could have importance for our own health, how are we supposed to react? News about health abounds, but how much of it is really useful?
It is important to remember that “news” is the business of reporting things that are new. Consequently, even weak medical and scientific studies that report surprising findings tend to appear in the media in preference to strong studies that confirm what we had already suspected.
A strong study that finds that eating too many cheeseburgers increases risk of heart disease is not news, but how about a weak study that finds that people who eat more cheeseburgers live longer? That’s the type of “man-bites-dog” story that makes the news.
Because it’s the surprising medical discoveries that make news, the media projects an impression that the overall process of discovery in medicine is unpredictable. We medical researchers seem to be constantly flip-flopping. What was good for us last week is now bad, and what was once bad for us can now save our lives. Flip-flops in medical advice can be particularly confusing and result in a sense of cynicism that can impede healthy choices.
Here’s a good example: A recent study concluded that being overweight might not be harmful. After being barraged for months by the message that obesity is the new plague, it was especially surprising to then hear that some new study found that being overweight was really not so bad after all.
What is going on? The conclusion that being overweight is no longer harmful to health was presented by the authors of the study – and reflected by the media – as the most definitive study to date on the question of health effects of obesity. But that conclusion was based mostly on deaths observed from a group of only about 10,000 people followed for just a few years.
That is little evidence compared to the body of published work on health risks from obesity that include, in total, millions of people followed for much longer periods of time. The overall evidence is clear: Being overweight is harmful to health. This new study does raise some interesting questions, but it hardly overturns the much larger body of evidence that serves as the basis of sound expert recommendations to avoid excessive weight.
When a new study is published that doesn’t confirm the findings from many previous studies, medical scientists are now properly conditioned not to assume that all prior knowledge has suddenly been invalidated. We have come to regard surprising findings as opportunities to inform the overall process of discovery.
Many startling findings are later found to be false signals, either resulting from some differences in study methodology, or just flukes – random variations arising from small studies that do not, in the broader picture, change the totality of evidence. Scientists have come to understand that single studies will rarely change the consensus conclusions about well-studied issues.
This is more difficult for the public, though, who get most of their medical research information filtered through the media. The public believes that media reports are generally factual – and indeed they usually are – but it does not follow that each new medical study considered in isolation provides a sound basis for decisions about health.
Reliable medical discovery rarely comes from a single study. The process of medical discovery builds from multiple studies that together lead to sound and stable conclusions that can be translated into reliable medical advice. It should be expected that there will be studies along the way that seem to contradict prior knowledge derived from the larger body of previous evidence.
Some amount of inconsistency across different studies is to be expected. Unfortunately, it is these very inconsistencies that tend to become “news.” Expert panels convened to examine all the evidence on a topic rarely reverse their conclusions or advice from a single study. Neither should we.
Why then do we see so many flip-flop stories in the media? There is plenty of blame to share. The mission and motives of medical scientists and journalists are similar when it comes to generating news. Each is under pressure to uncover new facts, and to publicize the findings to peers and to the public. Scientists often over-interpret the importance of findings from studies in which they are personally invested, and journalists often amplify this over-interpretation in the stories and headlines they write.
The interpretation of news in the medical sciences is further complicated when a report is sponsored by a company that spins the reported results to favor its product. It is easy to see why the public is often confused.
Who among us does not want to prevent disease? Who among us therefore does not pay attention to news of a reported “breakthrough” that suggests changes in the way we should live? Questions such as whether a particular food is good or bad for us or what we should weigh are questions we rightfully care about.
But the direction of medical discovery does not always follow a straight line. Medical scientists expect contradictions between individual studies. But because those very contradictions become the news, the general public has come to believe that medical scientists are constantly flip-flopping.
All of us – scientists, reporters and readers – need to be much more careful about how we treat scientific news. Scientists need to better explain the practical interpretation of study findings; journalists need to resist the temptation to turn each new finding into major news; and readers need to become much more skeptical of the importance of each new study.
When scientists overstate their findings, and when reporters sensationalize their stories, the result can be public confusion, anger and cynicism about health information.
Tim Byers is vice chair of preventive medicine and biometrics at CU Health Sciences Center. Richard Byyny is director of the Center for Health Policy at the CU hospital.
