Gary Schwitzer is publisher and founder of HealthNewsReview.org. He has been a health care journalist for 45 years. Twitter: @garyschwitzer
We write about the limitations of drawing conclusions from observational studies quite a bit.
Why? Because there are ever more such studies and ever more news stories and PR news releases about such studies. And few include an important discussion of what these studies can do and what they can’t.
Please note: Observational studies (as with the research that linked smoking to cancer and other problems) can indeed pile up such overwhelming evidence that it would be prudent to make public health recommendations on that basis. In fact, in some cases, observational data from large numbers of people that show associations previously found in other large studies may be stronger than some data from some randomized clinical trials. Not all studies are equal. There can be strengths or biases in any study. However, an observational study cannot prove cause and effect. Statistical association is not proof of cause-and-effect. It is not unimportant. But no one should make it more than what it is. (For more on the limitations of observational studies, see the three links at the end of this article.) For years we have offered guidance to writers about the language that should be avoided when discussing observational data – and language that is better.
So when you analyze news coverage every day as we have done for more than 12 years, you can’t help but be blown away by the amount of news attention that is given to observational studies, often without discussion of limitations.
Our first early sweep of national health care news this morning came up with all of the following – the first three of which come from the European Society of Cardiology meeting:
Eating this much chocolate could cut heart disease risk by 13 percent. – Newsweek (which borrowed from The Telegraph and The Daily Mail – a troubling practice that suggests very little independent vetting is being done by a news organization that was once a leader.)
New Wrinkle in Heart Health: Furrowed Brows May Bode Ill – HealthDay. The story did include this line, “But the study did not prove that forehead wrinkles cause heart risks to rise, and other heart experts remained skeptical.” Given that, why was the story worth publishing?
Deep forehead wrinkles may signal heart disease risk – USA Today. And yes, past observational studies have shown statistical associations between ear lobe creases and heart attack or stroke. Does that mean people who spot wrinkles/creases should run in for full body or full head wrinkle scans? Hardly. So how is this news important in readers’ lives?
(See other news on observational data from the European Society of Cardiology meeting in another post on our site today – What you need to know when it comes to bad news about “good” cholesterol.)
Can an Anti-Inflammatory Diet Improve Your Mental Health? – US News & World Report. The long piece is centered around one woman whose doctor ordered “30-some blood tests” before diagnosing her with this: “Your body is a forest fire,” and then prescribing a strict anti-inflammatory diet. So add tyranny of the anecdote as one more flaw in this story.
You could argue that none of these news items was worth publishing. None provided evidence for news you can use.
Instead of reporting on these studies, I would urge journalists to report more on articles like these that are also in the medical literature:
Opinions on other issues in news, journals, PR, advertising, marketing
In researching this @bopinon column on medical misinformation, I reached @garyschwitzer who said the information pollution problem goes back to the 1980s, when PR people started tempting reporters with easy, uplifting, prepackaged hype.
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Comments (1)
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Mimi Griffith
September 4, 2018 at 8:36 amCan you please write about the weaknesses and strengths of meta-analysis studies? I don’t think most news outlets have a clue.
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