One-in-Four? NFL Scrambles

At least one in four former National Football League players who died from 2016 to 2021 had chronic traumatic encephalopathy, according to a peer-reviewed study, raising fresh questions about the future of America’s most-watched sport.

Story Highlights

A British Medical Journal study found 215 CTE cases among 235 examined former players, a minimum of 24.5% of all who died in the period.
The estimate is conservative because 643 deceased players were not examined, so the true rate could be higher.
Families reported memory loss, mood swings, and addiction among reasons for brain donation.
The National Football League says it is working to reduce head impacts and concussions.

What the new study actually found

Researchers examined brains from 235 of 878 former National Football League players who died between 2016 and 2021. They found chronic traumatic encephalopathy in 215 of those examined, and used that to set a minimum prevalence estimate of 24.5% among all 878 who died in that window. The sample included players who died at different ages and across eras, suggesting the disease is not limited to one generation of play. The headline number reflects a floor, not a full population rate.

The estimate is conservative because most deceased players in that period were not part of the examined group. Six hundred forty-three brains were not studied, and some likely had the disease as well. Families reported symptoms such as memory loss, reduced executive function, mood swings, and addiction when deciding to donate, which fits known concerns about the condition’s impact on behavior and thinking. The study tracks with the view that repeated head impacts, including smaller hits, drive risk over time.

Why selection and diagnosis limits matter

The sample relied on donated brains. That design can skew results because families worried about symptoms are more likely to donate. This selection bias means the study cannot prove the exact rate among all former or current players. Chronic traumatic encephalopathy can be definitively diagnosed only after death, which blocks clean estimates in living players and slows agreement on prevalence. These limits do not erase the signal, but they shape how far we can generalize it.

Media headlines that say “at least one in four” are accurate for a minimum estimate, but can be read as a final answer. That risk of overreach is built into this kind of research. League-friendly voices often lean on the same limits to argue for caution, emphasizing uncertainty or other factors. Yet sports medicine experts continue to link the disease to cumulative head impacts, not just diagnosed concussions. The key tension is simple: the method is imperfect, but the signal is strong and persistent.

How the league and public institutions are responding

The National Football League said it “continuously strives to make the game of football safer, including by implementing strategies to reduce concussions and head impacts,” focusing attention on rule changes, equipment, and practice limits rather than on prevalence debates. Commentators also stress mitigation, calling for stronger long-term health support for players, even as they accept that some risk will remain in a collision sport. That framing keeps the sport viable while acknowledging occupational hazards.

I’ve been getting many calls on the new CTE study released yesterday.

Here are the numbers.

Between 2016 and 2021, a total of 878 former NFL players died. Of those, 235 donated their brains to research. From the group of 235, 215 players brains had CTE.

This is a crisis.

— Allan Walsh🏒 (@walsha) August 26, 2026

Fans across ideologies see a deeper pattern they recognize from other sectors: institutions react after harm is clear, research lags, and accountability gets diffused. Families face the costs when systems move slow. Policymakers could close basic gaps without ending football. Steps include transparent data access, independent research oversight, and better lifetime care for retirees. Those moves respect the sport’s place in American life while honoring the duty to tell the truth about risk and to protect workers on the field.

What to watch next

Independent access to the full British Medical Journal article and methods will help test how representative the examined group is and how pathology was confirmed. Clearer position-by-position and exposure-duration data could show where risk concentrates, guiding safer play and smarter limits. Progress on living-diagnosis tools, tied to postmortem validation, would let doctors measure risk earlier and track it over time. Until then, the core tradeoff is stark: our top sport carries a real brain risk that we still cannot fully measure.