Study finds at least 25% of former NFL players who died 2016 to 2021 had CTE

Where the estimate stands now

A study published Aug. 25, 2026, in The BMJ produced a new range for how often CTE was present at death among former NFL players who died in a recent period. Investigators at Boston University, Spaulding Rehabilitation Hospital and the Concussion & CTE Foundation identified 1,712 ex-players who died from 2008 through 2021 and found that 338 had donated brains. Of those donors, 315, or 93.2 percent, showed CTE pathology. In the narrower 2016-2021 window, which the authors described as more representative because donations were more frequent, 235 brains were donated and 215 had CTE. That produces a prevalence estimate of at least 24.5 percent and possibly as high as 97.7 percent. Lead author Daniel Daneshvar said the true rate "is somewhere in the middle". Community brain bank studies, by contrast, have found CTE in under 1 percent of the general population.

How the study reached its range

Since the diagnosis currently requires postmortem brain tissue, the team built a denominator of all former NFL players who died during the study period using demographic data and death certificates obtained from the CDC. They then focused on 2016-2021, when brain donation was most frequent. The lower bound reflects confirmed cases among donated brains; the upper bound assumes all former players had CTE except the 20 whose brains were definitively cleared. The authors caution that brain donors may overrepresent symptomatic players, so the range is not a direct measurement of CTE among living players.

Dementia and what the study does not show

Among the 315 donors with CTE, 193, or 61.3 percent, met criteria for clinician-diagnosed dementia. For donors with Stage IV CTE, the most severe form, 90.4 percent had dementia. Yet 40 percent of CTE-free brains also had dementia. The authors warn that the study cannot determine how common CTE is among living players, and it does not prove that CTE by itself caused dementia. Donors often had other neurodegenerative and vascular diseases as well, and only about half of those whose sole neurodegenerative finding was CTE had dementia. The authors caution against extending these findings to players at different football levels or to athletes in other contact sports until more research is done.

The path to this point

NPR reported that CTE was first diagnosed in a former NFL player in 2005. The average age at death among brain donors was about 66, so most donors played before recent safety changes; neurosurgeon Randall Chesnut, who was not involved in the research, said the sample may not reflect the NFL in 2026. In 2011, the league's labor deal reduced how many contact practices teams could hold during a season. Five years later, the Ivy League prohibited full-contact tackling in practices. Also in 2016, the U.S. Supreme Court cleared the way for the NFL's concussion settlement with retired players. Daneshvar said nearly 70 percent of head impacts occur in practice, so cutting practice contact can lower cumulative head impact burden without changing game minutes. The NFL said it "continuously strives to make the game of football safer," including reducing concussions and head impacts. The NFLPA called the findings a "sobering reminder" and a "call to action" to advance research and improve access to care. Rachel Grashow, director of epidemiological research initiatives at the Football Players Health Study at Harvard and not involved in the study, said treatable conditions tied to head injury, such as sleep apnea, high blood pressure and low testosterone, can produce symptoms associated with CTE. The study team expects a further analysis of CTE prevalence among all NFL players at death within months.