At least 25% of former NFL players who died from 2016-21 had the degenerative brain disease CTE, according to a study posted Tuesday by the British Medical Journal.
The study was conducted by Mass General Brigham, Boston University and the Concussion & CTE Foundation.
Researchers examined samples of the brains from some of the 878 players who had appeared in at least one NFL game, in any year, and died during that six-year period. CTE, or chronic traumatic encephalopathy, has been linked to repeated head injuries and can only be diagnosed after death.
Of those donated brains that were tested, 215 of them showed CTE.
The NFL Players Association called the study a “sobering reminder that football carries real risks.”
“Those risks can have lasting consequences for players and their families,” the NFLPA said in a statement to ESPN. “It also reinforces one of the NFLPA’s core priorities: improving player safety and supporting players throughout their lives, both during and after their careers.
“The findings should serve as a call to action across the entire football ecosystem. We all share a responsibility to advance research, improve access to care, develop better treatments, and support those affected by the long-term impacts of the game.”
The NFL said it “continuously strives to make the game of football safer, including by implementing strategies to reduce concussions and head impacts.”
“The NFL remains committed to ensuring that the NFL community has access to a robust — and expanding — set of resources to enhance their physical and mental well-being,” the league said in a statement.
Dr. Daniel Daneshvar, the study’s lead author, said that the estimate of 25% is on the “low end.” He said the maximum possible prevalence is around 97%, with the true rate of CTE “somewhere in the middle.”
A higher presence of CTE is probable but not possible to calculate because of the number of players who donated their brains. Of the 878 deaths, only 235 players donated their brains.
The study also found that more than 91% of the samples submitted — 215 — were linked to Stage IV CTE, the most advanced stage, and met the criteria for dementia.
Daneshvar said the risks of CTE can be mitigated by eliminating hits during practice sessions and prohibiting children from playing tackle football.
