Publicity over a new study, presented last week in the Journal of the American Medical Association, has us scared for football players. But should it?
The article, entitled Clinicopathological Evaluation of Chronic Traumatic Encephalopathy (CTE) in Players of American Football, by Dr. Jesse Mez, an assistant professor of neurology at Boston University’s Alzheimer’s Disease Center, and colleagues, suggest that CTE may be related to prior participation in football, and the news media has run wild with the conclusion. I contend, however, that this is a poorly constructed study. In fact, it’s really not even a scientific study; it’s more of an observation that doesn’t warrant publication.
The first problem is that this study is based on a “convenience sample” of deceased football players at a variety of playing levels (pre high school, high school, college and professional). Those studied were picked by the scientists from families who indicated that the individuals whose brains were donated had cognitive, mood or dementia problems. From a scientific perspective, this represents a non-objective or biased group. For this study to be properly constructed, the experimental group of football players needs to be randomly chosen from all football players, regardless of any neurological problems. Otherwise, any observations made in the study only connect CTE to behavioral dysfunction, not necessarily football.
Second, there are no controls in this “study” — no brains from individuals who were not football players and who did not have behavioral problems. Without these control groups, we can’t conclude that the presence of CTE is associated with playing football.
A recent study published in June in the scientific journal, World Neurosurgery, concluded that, “it remains unclear whether [CTE] is a syndrome unique to repetitive head trauma, especially in contact sports, because the epidemiology has been difficult to establish. In particular, research to date has had a denominator problem in not establishing the total number of potential cases at risk for developing CTE.”
In another article, published in October in the Journal of Vascular and Interventional Neurology, scientists concluded that further studies should be conducted to correlate the number and type of blows to the head associated with developing chronic traumatic brain injury symptoms. Again, this suggests that a relationship between concussion and CTEs is not well defined.
I am not, by any means, arguing that CTE is not associated with multiple concussions or subconcussive blows to the head. In fact, evidence suggests that it probably is related. I am suggesting that this particular “study” should not have been published. Once published, we assume, in many cases, that it is fact, and in my opinion, this report does not make the case.
Consider the effect that this may have on the sports community. A parent reads the publicity associated with it and immediately assumes an association between CTE and football. A child is kept from the sport because of it.
Two days after this “study” was presented, Baltimore Raven’s offensive lineman John Urschel announced his retirement from professional football. In addition to being a skilled athlete, Mr. Urschel is a brilliant mathematician, but I would hope that, and I expect that, his decision was not based solely on this study, although team sources said his decision was linked to these results.
What this study does show is that, in a group of selected formal football players with emotional, behavioral, mood and dementia pathology, a very high proportion of them had evidence of CTE. The authors suggest that CTE may be related to prior participation in football — and it may very well be related, but this study doesn’t begin to prove it.
A.J. Russo is a visiting assistant professor at Drew University and a resident of Mount Airy; his email is firstname.lastname@example.org.