How Common Is CTE in NFL Players? New Study Finds at Least 1 in 4 Had It at Death
- Football Nation
- 1 day ago
- 4 min read
A new population based study published on August 25 in The BMJ confirms that at least 24.5 percent of the former NFL players in its death cohort had chronic traumatic encephalopathy, or CTE. The direct answer is therefore at least one in four among the 878 former players who appeared in an NFL game and died from 2016 through 2021. That is a conservative floor, not a precise rate for every former or current player.
Researchers identified CTE in 215 donated brains. Because 643 players in the cohort did not donate a brain, the study cannot determine one exact prevalence figure. It can establish that 215 confirmed cases divided by all 878 deaths equals 24.5 percent.
What the new NFL CTE study actually found
The study used a population based denominator instead of reporting only the percentage among brain donors. Of the 878 deaths, 235 brains were donated and 215 showed CTE pathology, a 91.4 percent rate within the donor group. The accompanying Mass General Brigham summary reports that 61.3 percent of NFL donors with CTE met clinical criteria for dementia. More advanced Stage IV disease was strongly associated with dementia and functional impairment.
Measure | Verified result |
|---|---|
Former NFL players in the death cohort | 878 |
Players whose brains were donated | 235 |
Donated brains with CTE pathology | 215 |
CTE rate among donated brains | 91.4% |
Confirmed lower bound across all 878 deaths | 24.5% |
Extreme upper boundary if every non donor had CTE | 97.7% |
NFL donors with CTE who met clinical dementia criteria | 61.3% |
The 97.7 percent figure is not the study's estimate of the true rate. It is the mathematical upper boundary produced by assuming every player whose brain was not examined also had CTE. The authors say both extremes are unlikely and the true prevalence lies somewhere between them.
Why this matters for the NFL now
The result shifts the conversation from whether CTE occurs in former NFL players to how large the burden may be. It also sharpens the distinction between diagnosing a concussion and reducing all repetitive head impacts. Football Nation's guide to Guardian Caps explains one equipment response, while the blue medical tent is part of the sideline evaluation process after a possible injury.
The NFL says its 2025 season produced a record 538 in game concussion evaluations and 26 medical timeouts, according to the league's latest safety data. Those systems can identify and manage acute events. They do not by themselves prove that long term exposure risk has been eliminated.
What changes next
The immediate pressure is on exposure reduction, enforcement, equipment research and long term care. Rules against a blindside block, a dangerous facemask foul, illegal contact that becomes roughing the passer, and a chop block all remove specific avoidable hazards. Protections for a long snapper show how the rulebook can also target a vulnerable player in a predictable position.
The league and union already operate a formal concussion return protocol. The stronger policy question raised by this study is whether exposure should be tracked across practices, games and careers with enough consistency to measure cumulative risk, rather than relying only on diagnosed concussions.
The strongest counterpoint and uncertainty
This was a retrospective study of players who died, not a random sample of every person who ever played in the NFL. Brain donors may differ from non donors because families concerned about symptoms may be more likely to donate. The cohort also combines players from different eras, positions, career lengths and exposure levels. Those limits prevent the 91.4 percent donor figure from being applied to all NFL players.
The linked BMJ editorial argues that uncertainty should not be confused with absence of risk. The population denominator gives researchers a defensible confirmed floor, while the wide interval shows why the next modeling work matters.
Can CTE be diagnosed in living NFL players?
No. CTE can currently be diagnosed definitively only after death through brain tissue examination. Symptoms such as memory problems, mood changes or impaired judgment can have other causes, including conditions that may be treatable. The study does not provide a test for a living player and should not be used to diagnose an individual.
A clear CTE explanation worth watching
The next factual checkpoint
The research team says a more refined prevalence estimate is expected after additional statistical work. The most useful next release will narrow the range while accounting for donor selection, playing history and exposure differences. Replication in other football cohorts would strengthen any estimate.
Football Nation verdict
This study clears the national importance threshold because it replaces speculation with a confirmed minimum: at least 215 of 878 former NFL players in the cohort had CTE at death. The honest interpretation is not that every player faces the same risk. It is that one in four is now the lowest defensible figure for this defined group, and the real burden is likely higher. That makes continued exposure reduction and transparent long term tracking a football issue, not merely a medical footnote.
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