Among NFL players who died 2008–2023, study finds nearly 75% had CTE brain disease

How researchers reached the estimate

Published in JAMA Network Open, the study examined CTE among NFL players who died between 2008 and 2023. It found an estimated prevalence of 74.5%. CTE was found in 94% of brain donors. Boston University said donors may be more likely to have symptoms associated with the disease, creating selection bias and uncertainty about how representative they are of all NFL players. Researchers adjusted the donor rate using an estimated selection ratio.

Players call for safer football

Former NFL quarterback Matt Hasselbeck, an ambassador for the study, said the findings should inform efforts to make football safer. He said the figures should not be accepted for the next generation of players.

A former linebacker described the risks players may face, including being knocked unconscious or undergoing surgery. He also said he understood what he was signing up for when he chose to play, while viewing efforts to improve safety positively.

League and union cite support

The NFL said it works to make football safer, including through strategies to reduce concussions and head impacts. It pointed to Guardian Caps and rule changes intended to protect players.

The league also said it offers resources for the physical and mental well-being of its community and urged former players with health concerns to seek help. The NFL Players Association said it supports research, invests in well-being resources and is expanding access to care.