Just when you thought there was another upside to living with the over-caffeinated jitters, along comes the healthcare news police to throw cold water on the still warm grounds.
Foxnews.com, HealthDay and assorted other news outlets recently reported glad tidings for female coffee drinkers. A study in the February issue of Cancer Epidemiology, Biomarkers & Prevention showed women who drank four cups of coffee a day had an 18% lower risk of developing endometrial cancer, which claims about 10,000 lives a year, compared with women who drank less than a cup a day. The study was based on the dietary habits of 456,000 women who self-reported their choices in two large studies.
Not so fast, says former University of Minnesota journalism professor Gary Schwitzer, who runs the website HealthNewsReview.org and uses expert panels to review media accounts of medical studies. The news release put out by the American Association for Cancer Research never mentioned that association doesn't equal causation, and none of the news reports contained that caveat high up in their stories, he said.
“I got about 100 returns on a search result looking for news of coffee and endometrial cancer risk,” he wrote on his website. “Almost none that I saw made any mention of observational studies and their limits.”
For the record, here is his cautionary advice for observational study authors, their PR spokespersons and the journalists who write them up: “Observational studies cannot control for all of the other inevitable, often unmeasurable, exposures or factors that may actually be causing the results. Thus, any 'link' between cause and effect in observational studies is speculative at best.”
Follow Merrill Goozner on Twitter: @MHgoozner