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Licorice & pregnancy…caffeine & longer life: Distorted news stories about observational research

Gary Schwitzer is publisher of HealthNewsReview.org.  He knows the contribution that observational research can make, but frequently writes about miscommunication of such findings.  He tweets as @garyschwitzer, or under our project handle, @HealthNewsRevu.

Step back. Breathe deeply. Join us in sucking in some recent research news coverage.

Coughing on cacophony of coffee/caffeine news

USA Today reported, “Caffeine may lead to a longer life.”

Or, it may not, the story could just as easily–and accurately– have reported.

Instead, it makes a leap to this news-you-can use assertion: “Perk up. That daily cup of coffee could guarantee many more mornings.”

Guarantee?

The story mentions a study but doesn’t link to a study. Rather, it links to a Stanford news release that is much better than the more widely-distributed USA Today story. The Stanford release only refers to an “association” and a “correlation,” but never to proof of cause-and-effect. That’s because the work was based on an analysis of blood samples, mouse research, and an analysis of patient data.

Important, but not a level of evidence that should be framed as a “guarantee” of longer life.

The wisdom of the crowds reacting to shoddy observational study news

The New York Times reported, “Licorice During Pregnancy Tied to Problems in Children.”

It began: “Pregnant women may want to avoid licorice, which may affect the cognitive abilities of their children, a study suggests.”

It ended: “We know that there are limitations in observational studies like this,” said the lead author.

Yes, we certainly do know that. But burying the caveat at the end of the story may only further hide that fact from readers who get drawn in by the headline and first sentence.  And allocating just 250 words to health science news is hardly in the best tradition of the New York Times. But, as another Minnesotan wrote, the Times they are a-changin’.

What this collection of words didn’t tell you was that the study in question assumed that the women who consumed more than the equivalent of 8.8 ounces of pure licorice a week are no different than the women in the study who consumed little or none.

But you–and the Times–should be asking: What could be other, confounding factors that might help explain the results? Maybe licorice wasn’t the only candy or sweetener the women were consuming in greater quantities. What else might be different in the upbringing of the children born of the big licorice eaters from the upbringing of offspring of the lesser licorice eaters?  For instance, maybe a mother who would consume more than the equivalent of 8.8 ounces a week of pure licorice would have a different notion of what she would allow her kids to eat and drink during these critical childhood years.

No, I’m not trying to blame moms/parents for one more thing, but these are the kinds of questions that should come to mind when thinking of confounding factors that can influence observational research results.

Smart readers are catching on, tired of the flood of fearful or fanciful health care news based on inadequately explained observational research. Times readers left these comments:

  • “Come on, NYT — I expect better. Only 451 women out of the original 1,049-member cohort agreed to participate in the follow-up, and of those, only 124 reported consuming more than a tiny amount of licorice. So we have a headline based on 124 children born in Finland in 1998 whose mothers reported consuming more than minimal amounts of licorice. I have no skin in this game — I hate licorice and I’m not pregnant — but I am really over bad science reporting. Do better.”
  • “One of these days the Health section will report the development of Mommy Chow, a scientifically developed complete nutrition source for pregnant women so they will never have to make any food choices whatsoever.”
  • “Association is not cause and effect. Could it be that women eating this much licorice are consuming more junk food and processed foods than other women? Could it be that their diets taken on whole are poor?”
  • “Correlation is not causation. NYT, why do you so rarely make this point when you report these kinds of observational results?”

So, journalists, if you aren’t getting the message from us after nearly 11 years of trying to get these points across, you’d better listen to your readers. You’re losing them. And this is one reason why.

And readers, please keep coming back here to continue your education and to sharpen your critical thinking about all those studies you hear about every day.

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