Prevalence of CTE in NFL Football Players

Repetitive blows to the head can lead to a debilitating chronic brain disorder called chronic traumatic encephalopathy (CTE) later in life. CTE is of particular concern to football players, boxers, and even soccer players. How common is CTE among certain athlete groups, and should we be concerned?

Of course we should be concerned. We would be remiss if we didn't try to find out how and why it is happening to our athletes, and how to prevent it in the future. But we should not scare people needlessly with sensationalist headlines. Take, for example, a CNN news headline: "Study: CTE in 99% of dead NFL players". Or this one in the Daily Mail (a British journal): "Biggest Ever NFL brain study diagnoses CTE in 99% of deceased players' brains". Read more closely and you find that the correct statement is that CTE was found in 99% of deceased ex-NFL players whose brains were donated to scientific research by their relatives (my emphasis). It's not a group that is representative of all deceased NFL players, by any means. It is likely that many if not most of these relatives donated their loved-ones' brains because they already suspected the presence of CTE based on their loved ones' behavioral symptoms while still alive. A definitive diagnosis of CTE can only be made at autopsy. CTE generally isn't looked for in a deceased player without symptoms of CTE, so in fact we really don't know how prevalent it is.

Clearly, CTE is present in many ex-NFL players, and its time to do something about it. The numbers may turn out to be higher than initially thought, and that would be sad. But there's no evidence that it's as prevalent as 99%, at least at the moment. Let's approach this problem with level heads and open minds.