At least 1 in 4 NFL players are likely to end up with the brain disease chronic traumatic encephalopathy, or CTE.
That’s the finding of Boston-based researchers who set out to determine just how common the neurodegenerative disease may be. CTE is linked to repeated hits to the head — including those that occur while playing football.
But identifying CTE is a challenge; it cannot be diagnosed until after death, by examining brain tissue.
For this study, researchers at Mass General Brigham, Boston University and the Concussion & CTE Foundation identified 878 former NFL players who died between 2016 and 2021. They examined brains donated by 235 of those former players. They determined at least 25% of players had CTE, though the true prevalence is likely higher because they were unable to study every former player’s brain.
Critics have said the NFL and others haven’t done enough to protect players from brain injuries despite years of evidence connecting CTE to football.
The NFL told WBUR the league “continuously strives to make the game of football safer, including by implementing strategies to reduce concussions and head impacts.”
Dr. Daniel Daneshvar, chair of physical medicine and rehabilitation at Mass General Brigham, spoke with WBUR about the research, which was published in the journal The BMJ.
This interview has been lightly edited and condensed for clarity:
How do your findings here build on what we already know about CTE prevalence?
Daneshvar: What we know about CTE prevalence is that in the community — in people who don’t get repeated hits to the head — the rate of CTE is less than 1% at death.
What we found here is by looking at a cohort of NFL players, the absolute minimum rate of CTE in these NFL players was 25%. The absolute maximum rate was 98%. And so we know the true prevalence is somewhere in that range.
You say these numbers are a “wake-up call” for the NFL. What do you hope people take away from this research?
Daneshvar: We need to start pivoting resources into better treating — and ultimately curing this disease.
We know that the head impacts that these athletes experienced do not only occur at the NFL level. They also occurred at the college level, the high school level, in some cases the youth level. And all of those cumulative hits to the head, the cumulative force of those hits to the head — that’s what drives the risk of this disease process. So we need to be better at mitigating and eliminating the unnecessary g-force to the head that athletes experience.
There have been advances in helmet technology and now the Guardian Cap helmet covers. What more needs to be done?
Daneshvar: The Guardian caps, those in lab settings have been shown to attenuate the force of impacts by about a percent or two. So when you’re talking about a 30g impact, you’re making that 30g impact a 29.7g impact. You’re not meaningfully changing the underlying force dynamics.
The best way to prevent diseases that are associated with this cumulative g-force is by eliminating that unnecessary hit altogether.
The helmets that NFL players are wearing today are different from the helmets worn by the players you studied. So how do you apply this research to what we see on the field today?
Daneshvar: Although there’s been some changes in equipment, there’s also been changes in how players play the game. They start younger now. They’re bigger, faster and stronger than they’ve ever been before. And nine individuals in this study — they unfortunately passed away in their twenties, meaning they played the modern game.
We have not found meaningful differences in rule changes or other changes in terms of what it means for the players’ risk.
I know this is a vast topic. What am I missing here — is there anything else that you want to add?
Daneshvar: The issue of CTE has been linked to concussions. But what we’re increasingly realizing is it’s not concussions that are driving the risk of CTE, it’s the cumulative force to the head — the thousands to tens of thousands of accumulated hits to the head that result in the biggest risk of CTE.
The important thing to note for individuals who have experienced these repeated hits to the head over years, who might be concerned about themselves, or for family members who might be concerned about their loved ones, is that many of the symptoms we believe to be associated with CTE are treatable. There are ways to get better.
So if someone is experiencing symptoms right now, they should reach out to a medical professional?
Daneshvar: Exactly. People get better with treatment. Our patients in clinic get better once they’re treated.
Disordered sleep or undiagnosed attention issues or problems with memory — that can be treated with medications. There are a lot of different ways that we can intervene to help with depression, to help with emotional dysregulation. There are things that we can do to help people get better — while we work towards a cure.
Editor’s note: Boston University owns WBUR’s broadcast license. WBUR is editorially independent.
This article was originally published on WBUR.org.
