IPM Take
The argument over football and brain disease has spent too long hiding behind uncertainty.
Yes, brain-bank studies are affected by selection bias. Yes, CTE still cannot be diagnosed definitively during life. Yes, not every former player has the same exposure, vulnerability or outcome. But uncertainty is not innocence.
The BMJ data do not give a perfect prevalence estimate. They give something harder to ignore: even under conservative assumptions, the burden of CTE among deceased former NFL players is large enough that prevention, monitoring and long-term care can no longer be treated as optional reputational management.
Executive Summary
A study published in The BMJ assessed chronic traumatic encephalopathy, or CTE, among deceased former National Football League players using death records and brain-bank data.
Across the broader study period, 1,712 former NFL players were identified as having died, and 338 brains were studied. Among those donated brains, 315, or 93.2%, had CTE. Because donation is not random and families may be more likely to donate when symptoms are suspected, that figure cannot be treated as prevalence among all former NFL players.
The study also estimated CTE prevalence using conservative assumptions. Public reporting of the study noted that among former NFL players who died between 2016 and 2021, at least around one in four had CTE when all deaths in that period were included in the denominator.
The study reinforces the need for better prevention, exposure reduction, clinical monitoring and support for former athletes. It does not make CTE diagnosable in living patients by itself.
Why it matters
- Patients / advocates: Former athletes and families need recognition, support and research pathways that do not require death before the disease is counted.
- Clinicians: CTE remains difficult to diagnose during life, but histories of repetitive head impact should inform neuropsychiatric assessment and long-term monitoring.
- Policymakers: Sports governance cannot rely on voluntary risk language while evidence of long-term brain harm accumulates.
- Civil society: The cultural value of football does not remove the obligation to reduce preventable harm.
The brain has become football’s most politically inconvenient organ. It is easier to celebrate toughness, speed and spectacle than to ask what repeated head impacts may mean decades later, when the stadium is gone and a family is trying to understand mood change, cognitive decline, impulsivity or dementia.
The BMJ study does not allow a simple slogan. The highest figure, 93.2% CTE among donated brains, reflects a selected brain-bank population and should not be presented as the rate among all former NFL players. That caveat matters, and serious science should keep it visible.
But the caveat does not make the problem disappear. When conservative methods still suggest a substantial burden among deceased former players, the responsible response is not to retreat into technical uncertainty. It is to ask what level of preventable risk sports systems are willing to tolerate, and who carries the consequences after the careers end.
This is not only an NFL story. It is a policy story about occupational exposure, youth sports, concussion protocols, long-term follow-up, disability support and the right of athletes to understand risk before they are physically and financially committed to a system built around impact.
For IPM, the story is not that one paper settles every question on CTE. The story is that enough evidence now exists to make inaction look like a governance choice. Football can keep debating prevalence, but it cannot keep pretending that the brain cost is unknowable.
