A flawed news release, and the resulting coverage, of a study on breastfeeding and leukemia

Last week, we published a review of a JAMA Network news release about a study on breastfeeding and childhood leukemia risk. Our reviewers called the news release “incomplete” and “one-sided,” and said they were worried that the flawed presentation would lead to “a flurry of overblown media coverage.”

The study was a meta-analysis of previous case-control studies that had a number of key limitations that the release never commented on. The release glossed over those limitations entirely while emphasizing the headline message that “breastfeeding may lower risk of childhood leukemia.”

It’s worth reading the entire review to get a sense of what was missing. Because you won’t receive any of that context from some of the news reports that also lacked these crucial details.

• Fox News:  “Breast-feeding may lower risk of childhood leukemia, study says.”
• Time:  “Breastfeeding Linked to a Lower Risk of Cancer in Kids.”
• LA Times: “Breast-feeding may prevent 19% of childhood leukemia cases, study says”
• Medical Daily: “Breastfeeding Infant For More Than 6 Months Linked To Lower Risk Of Childhood Leukemia”

To be clear, we don’t know whether or not these stories were following the lead of the incomplete JAMA news release — and some of them included original reporting that most certainly went beyond the release.

But whether they relied on that release or not, all of the stories — like the release — lacked any mention of possible limitations to the study.

They expressed not one note of caution about the results, even though the study itself had four paragraphs and 450 words (more text than some of the resulting news stories!) dedicated to an extensive laundry list of such limitations.

I think this is an example of where a news release can make a real difference in the public discussion. It’s been established that — for better or worse — news coverage of health studies often reflects the framing of the news release that announces the results.

And if those news releases can do a better job, it follows that many stories based on those news releases will also become more complete and informative.

Not that we’re making excuses for media outlets that failed to dig deeper on an issue that cried out for more exploration. It certainly was possible to report more thoroughly on this issue, and many outlets did so. For example:

• USA Today quoted an expert who explained: “This type of study has inherent limitations because women whose children develop leukemia may remember things differently than those whose kids remain healthy.” USA Today added that, “At most, the analysis suggests an association between breastfeeding and reduced risk. But factors other than breastfeeding might also explain that link.”
• Tara Haelle, writing at Forbes, wasn’t content to simply repeat the “19% reduction” figure furnished by the release. She went much further, explaining that the reduction in risk suggested by the study — if breastfeeding does in fact cause fewer childhood cancers (an uncertain proposition) — would represent 0.8 fewer cancers per 100,000 children per year. Quoting an expert, she also challenged the study’s contention that breastfeeding is “a highly accessible, low-cost public health measure.” In fact, the expert said, women must “overcome routine maternity practices that undermine breastfeeding, lack of paid maternity leave, poor support from health professionals and outright hostility for feeding their babies outside the home.”
• Agence France-Presse also picked up on the limitations in inherent in this questionnaire-based research, noting that memories of parents whose children developed leukemia might not be reliable.  “The researchers had no way of assessing such an important potential problem, which could well have distorted their results,” the quoted expert says.

Yesterday, we highlighted a study showing that only 24% of news releases discuss any limitations to the study they report on, and a paltry 4% caution that observational studies cannot prove cause and effect.

Here’s a specific example of how that failure may lead to misinformation reaching the news consumer — and how different communicators can play a role in providing the context that readers need.