Op-ed: How one flawed study and irresponsible reporting launched a wave of CTE hysteria


Editor’s note: The following is an op-ed written by the authors of “Brainwashed: The Bad Science Behind CTE and the Plot to Destroy Football.”

The New York Times story dropped like a bomb on football and the medical community on the morning of July 25, 2017. Dr. Ann McKee, lead neuropathologist at the Boston University CTE Center, had examined the brains of 111 former NFL players and found signs of CTE, or Chronic Traumatic Encephalopathy, in 110 of them.

The news broke the internet, sent reporters scrambling to develop their own takes, and sealed the deal for millions of American parents, doctors, coaches and players. Finally, the link between playing football and developing a terrible neurodegenerative disease seemed ironclad.

As an ex-NFL player and a forensic neuropathologist, respectively, we both have an interest in solid science and sound policy that protects athletes, so we were alarmed by the CTE Center’s findings. In its wake, parents were removing their kids from Pop Warner leagues, experts were calling football “child abuse” and some states talked of banning tackle football altogether.

Then we took a closer look at the study that led to the Times story — apparently something few journalists had bothered to do. When we dug into the methodology, we were floored. The study was so badly flawed that it was nearly worthless. But that’s not what had been reported in practically every major media outlet in the world. Thanks to the barrage of sensationalist coverage, the “110 out of 111 brains” story had turned into a wildfire, and we were standing around with a couple of garden hoses, telling everybody to calm down.

That’s why we wrote our new book, “Brainwashed: The Bad Science Behind CTE and the Plot to Destroy Football” (Amplify, Oct. 23, 2018), and it’s why we’ve written this op-ed. We believe that when people know what we know, they’ll start asking tougher, smarter questions, and the “football causes CTE” connection will be revealed as the pseudoscience that it is.

Sure, that’s a provocative statement. How can we back it up? Let’s start with this: the study that produced the 110 out of 111 brains finding had no control group. Good research design requires a control group against which findings can be compared. In this case, the control group could have been brains from 100 athletes from sports other than football, brains from 100 men who had never played contact sports – any cohort that would have allowed the researchers to determine whether men of a certain age who hadn’t played in the NFL also showed signs of CTE. For some reason, this study didn’t have that.

Strike one.

Also, many of the 111 NFL brains were donated by deceased players’ family members specifically because the players had displayed symptoms of mood, cognitive or behavioral disorders. That’s selection bias. If you only look at brains from people who seem to have neurological problems, don’t be surprised when you find signs of those problems. A better approach would have been to randomly examine brains from some ex-players who exhibited mood, cognitive or behavioral issues as well as from some who didn’t. But this study didn’t do that.

Strike two.

Finally, there was no attempt made in the research paper (or the subsequent coverage) to control for or account for all the other factors in the lives of the deceased players that could have contributed to the condition of their brains. For example, nearly half the players had a history of substance abuse, suicidal thinking or a family history of psychiatric problems, but these were offered as possible results of CTE, not as possible independent causes of mood, cognitive or behavioral disorders.

In fact, 67 percent of the players found to have mild CTE also had substance abuse problems – and the abuse of some drugs can cause the key physical sign of CTE, deposits of a protein called tau in the brain. By the way, obesity, steroid use, cigarette smoking and chronic stress can also cause many of the physical signs of CTE. For example, 2016 research from the University of British Columbia found that anabolic steroid use causes CTE-like brain changes in mice, while research published in Frontiers in Neuroscience in 2014 found that obesity increases tau deposits in the brain. Were any of those former players obese, smokers or steroid users? Did they experience a lot of stress? We have no idea, because the study either didn’t ask or doesn’t tell us.

Strike three. You’re out.

Some of these limitations were discussed in the paper published on this work, but only in the last paragraph. In other words, they were buried. The researchers, especially BU, were all too willing to ride the wave of attention provided by the press without ever copping to the severe weaknesses in their work. As a result, the public is convinced that football causes CTE — and that anyone who says otherwise is a “denier” — based on work that would not have passed muster in a graduate-level research design course.

For the record, we’re not saying that CTE doesn’t exist or suggesting that taking repeated hits to the head is a good thing. Clearly, something is causing neurodegenerative disease in some athletes, and something is leaving CTE’s distinctive protein signature in their brains. But there’s so much we don’t know: what causes it, if impacts to the head are really involved, how much exposure is too much, what clinical symptoms (if any) these physical signs might cause later in life, if other factors are involved, and more. There are too many unanswered questions to justify the fear and hysteria.

What do we want? Simple. Pump the brakes. Let’s do transparent, collaborative, well-designed research that identifies the link between sports-related head trauma and neurodegenerative disease — if there is one. Let’s study other sports, like soccer. Let’s study women’s sports, not just men’s. Let’s do long-term prospective research that will tell us what decades of playing all kinds of sports does to the brain, what effects measures like protective gear and concussion rehab protocols have on outcomes, and if ex-athletes’ self-care after their careers are over can help them avoid CTE and other neurological diseases.

Let’s get good data from multiple sources and assess it based on diagnostic criteria created by the consensus of experts from multiple disciplines and multiple sources — rather than the criteria we use now, which were predominantly influenced by one source: Boston University. Let’s do science the way science is supposed to be done, and then act on that information, rather than on fear.

One of the arguments people are making is, “What’s the harm in being overcautious about hits to the head?” Good question. If the work of people like Dr. McKee is wrong and the media is peddling sensationalism and fear backed up by flimsy data, the harm is the impact this anxiety can have on people — young, old, and in between. The dire picture painted by the media could have a negative impact on mental health outcomes in athletes.

Right now, football players ranging from high schoolers to ex-pros are living in fear of CTE because they read inflammatory, fact-free stories in the press or because they forget where they put their car keys. Some pros are quitting the game in their twenties and giving up years of potential earnings because they fear that playing will cost them their futures. Bad information comes at a high cost. We not only have to get the science right; we have to get the story right.

Our kids, pro athletes, the great game of football and people who care about the truth deserve nothing less.

Merril Hoge is a former NFL running back who worked as an analyst at ESPN for 21 years, helping launch ESPN2, “NFL Live” and Fantasy Football, along with being a part of the longest-running NFL show on television, “NFL Matchup.”

Dr. Peter Cummings is board certified in anatomic pathology, neuropathology and forensic pathology. He is an Assistant Professor of Anatomy & Neurobiology with the Boston University School of Medicine. He earned his bachelor of arts from the University of Maine, his medical degree from the Royal College of Surgeons in Dublin, Ireland, and completed his pathology training at the University of Virginia. He also earned a master’s degree in pathology from Dalhousie University in Halifax, Nova Scotia.

“Brainwashed: The Bad Science Behind CTE and the Plot to Destroy Football” is published by Amplify. For more information, visit