Study: CTE Found in 215 of 235 Donated Brains From Former NFL Players

A new study of former NFL players who died between 2016 and 2021 has found that at least one in four suffered from chronic traumatic encephalopathy, a degenerative brain disease tied to repeated head trauma. Researchers examined records for 878 deceased players and received brain donations from 235 of them. Of those donations, 215 tested positive for CTE, a condition that can be confirmed only after death.

The findings come from Mass General Brigham, Boston University and the Concussion and CTE Foundation. Lead author Daniel Daneshvar, who chairs physical medicine and rehabilitation at Mass General Brigham and teaches at Harvard Medical School, noted that repeated traumatic brain injuries are a known driver of higher rates of neurodegenerative disease. NFL players in particular show roughly four times the rate of death from such conditions compared with the general population.

Dementia appeared frequently among the brain donors. The researchers called for stronger prevention efforts aimed at reducing repetitive head impacts throughout football, from youth leagues upward. They observed that most of the cumulative head trauma experienced by the former players occurred before they reached the NFL.

The NFL issued a statement emphasizing ongoing work to reduce concussions and head impacts through rule changes and equipment improvements. The league said it is expanding resources for players physical and mental health and urged former players to seek those services when needed.

The study adds to a growing body of evidence on long-term neurological risks in contact sports. It also underscores the limits of diagnosis during life, since CTE remains undetectable by current clinical tools. Public health experts have long argued that meaningful reductions in head impacts require changes at every level of the sport rather than isolated adjustments at the professional tier. The data released Tuesday provide one of the clearest snapshots yet of how common the disease has become among players who reached the highest level of the game.