How Common Is CTE in NFL Players, Really?
At least 1 in 4 former NFL players who died recently had CTE at death, and the true rate probably sits well above that. That's the finding of a new BMJ analysis covering every NFL player who died from 2008 to 2021. It corrects the famous 99% number for the fact that families donate brains when they suspect disease, and it lands on the same lever a decade of neuropathology has kept pointing to: years of tackle football, not the concussions someone remembers, drive who gets the disease. If you or someone you love plays, that's where the decision lives.
For a decade the loudest number in the CTE conversation was 99%: 110 of 111 former NFL players in the Boston brain bank had CTE at autopsy. The figure is real. It's also not what most people took it to mean. Families donate brains when they suspect something is wrong, so donation studies pile up the sick end of the distribution. Nobody knew what the rate looked like across everyone who played.
What this study did that earlier ones couldn't
Daneshvar and colleagues built the denominator: every NFL player from the hard-shell-helmet era who died between 2008 and 2021, all 1,712 of them. 338 donated their brains. Of those donors, 315 had CTE and about a third had the most severe, stage IV, form. Roughly 60% met criteria for dementia at death.
Then they modeled how much of that could be donation bias and asked what the true rate in the whole 1,712 could be. The floor came out to at least 1 in 4 for the 2016 to 2021 window. The plausible ceiling was 97.7%. That's a wide range, and the paper is honest about it. What it commits to is a lower bound a critic can't argue away: even under the most bias-friendly assumptions, at least a quarter of NFL players who died in that window had CTE. Because the donors were older men whose careers largely predated recent rule and equipment changes, the estimate speaks more to earlier eras than to today's NFL.
| Study or cohort | CTE rate | What it tells you |
|---|---|---|
| BMJ 2026, all NFL players who died 2008 to 2021 | At least 1 in 4, up to 97.7% | First population-based estimate; the honest range once donation bias is modeled out |
| Mez 2017, NFL brain donors | 110 of 111 (99%) | Selected donors; the number that made headlines and overshoots the truth |
| McKee 2023, contact-sport donors who died before 30 | 11 of 11 NFL donors; 63 of 152 total young donors had CTE | CTE shows up early, and most young CTE cases never played pro |
| Mayo Clinic tissue registry, community autopsies | 15% of former football players | Sampled from obituaries, not donations; a lower bound closer to community rates |
| Canadian Sports Brain Bank, elite football and hockey | 45.8% of football players | Independent brain bank; middle of the range, still far from a random sample |
Years of contact, not the concussions you remember
Once you know how common it is, the next question is who gets it. A decade of neuropathology has converged on one variable that predicts CTE better than anything else: total years of tackle football, weighted by how hard the hits were. The 2019 Mez analysis put the odds of CTE roughly doubling for every 2.6 years played. A 2023 accelerometer study of 631 donors then tied that to cumulative head-impact intensity, which predicted both whether someone had CTE and how severe it was. Self-reported concussion count didn't predict CTE on its own. Some confirmed CTE cases had no reported concussion history at all.
That last point is the one to sit with. The exposure driving the disease isn't the concussions someone remembers or the hits that made the news. It's the ordinary, unremarkable, subconcussive hits stacked on top of each other for a career. So the question a football family is actually deciding isn't whether your player had a diagnosed concussion. It's how many years and how many hits.
The one lever you can actually pull
If cumulative hits are what matter, then anything that lowers cumulative hits is where the action lives. Those levers work at the exposure level. A state rule capping full-contact high school practices at two days a week cut head impacts by about 42% across positions, and one prospective study found practice concussions dropped 57% with no rise in game concussions. The Heads Up Football coach program cut high school concussions by roughly a third and head impacts by nearly 40%. Delaying tackle start and shortening careers do the same thing more bluntly: fewer seasons in the years-played variable the pathology keeps tracking.
No study has yet shown any of these lowers CTE at autopsy, and none can right now, because CTE still can't be diagnosed while someone is alive. But they're the only known ways to move the one metric the disease keeps tracking, and they're within reach for a family, a coach, or a league that wants to act.
What's still missing
The number people quote has moved from 99% to at least 1 in 4, but the underlying story hasn't. CTE is common in men who played pro football, it tracks the years and hits they took rather than the concussions they remember, and shrinking that exposure is the only known way to lower an individual's odds. Two things would close the loop and don't yet exist: a prospective cohort of players followed from youth to autopsy, and a way to spot the disease in a living person. Until one arrives, the practical answer stays the same. Fewer years of contact, fewer hits per year, later starts, for more kids than the sport has been willing to admit.