Study Finds CTE in at Least One in Four Former NFL Players Who Died

A new study estimates that at least one in four former NFL players who died between 2016 and 2021 had chronic traumatic encephalopathy, or CTE. BBC Sport reported that researchers examined records for 878 former players who died during the six-year period and studied the brains of those donated for post-mortem analysis.

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Of the 878 players, 235 donated their brains to research. CTE was identified in 215 of those donors. The study, published in the British Medical Journal, calculated a conservative minimum prevalence of 24.5% across the full group and a maximum estimate of 97.7%. The large gap reflects the uncertainty involved when most of the players' brains were not available for examination.

CTE is a degenerative brain disease associated with repeated head impacts and can currently be diagnosed only after death. The study also found dementia was common among the brain donors. Lead author Daniel Daneshvar, an associate professor at Harvard Medical School, said the findings point to a higher prevalence of CTE among NFL players at death than previous community-based studies had shown.

Daneshvar also cited earlier research indicating that NFL players have roughly four times the rate of death from neurodegenerative disease seen in the general population. He said much of the head-impact exposure experienced by former NFL players occurred before they reached the league, including during college, high school and, in many cases, youth football.

The researchers urged the NFL and the wider sport to adopt prevention measures aimed at reducing repetitive head impacts at every level. Their conclusions do not establish one precise CTE rate for all former players, but the minimum estimate indicates the disease affected at least a substantial minority of those who died during the period studied.

In a response reported by BBC Sport, an NFL spokesperson said the league continues to pursue strategies designed to reduce concussions and head impacts, and remains committed to expanding physical and mental health resources for its community. The NFL's 2011 collective bargaining agreement limited contact practices, while a $1 billion settlement with more than 5,000 former players was agreed in 2016 following a class-action case.