Study: Lots of red meat increases mortality risk

Our Review Summary

This story covers a big study that reports a statistical association between a diet high in red meat and a higher death rate.

The report does a number of things well:

• It indicates early on that the results support previous findings and current recommendation about red meat, while adding new data.
• It quotes a variety of sources, including two self-interested representives of the meat industry who question the findings. This attention to the opposition enhances rather than undercuts the report’s credibility.
• It translates the findings into dinner-table terms: high consumption in this study is defined as about a quarter pound hamburger per day, low is 5 ounces per week. That’s really useful to readers.

The report has two significant shortcomings.

1. The language of the story – e.g., “lots of red meat increases mortality risk” – suggests that cause-and-effect has been established when this kind of observational study simply CAN NOT establish causation. It can only point to statistical association. The story never made that clear. So even discussing “risk” is an overstatement.
2. Then, when choosing to discuss “risk,” it used only relative data [“a 22 percent lower risk of death” by cancer for low-red eaters, for example], not the absolute data [1.3 percent compared to .06 percent]. But once the story started using “risk” terminology without explaining that cause-and-effect and risk cannot be firmly established by such a study, it had already missed the mark.

We know we hold the bar high with this expectation that stories explain the quality of the evidence. But it is not simply splitting hairs; it is inaccurate to use language that does not fit the evidence. Journalists and should consumers should review the excellent guest column by Mark Zweig and Emily DeVoto, entitled “Does The Language Fit the Evidence? – Association Versus Causation.”

One of our medical editors wrote to me about this topic:

“I can tell you, the average practicing physician (one of the presumed target audiences for the medical literature) has a less than firm grasp of this difference! I have been teaching evidence-based medicine for years, and it seems that our residents finally get this by the end, but I don’t think it’s a skill that was routinely taught in medical training before the past decade or two, nor one that sticks with most docs.”

None of this denigrates the importance of the study or the quality of the work. But all studies have limitations and news about research should explain those limitations.