At least one in four former National Football League (NFL) players who died between 2016 and 2021 were found to have had chronic traumatic encephalopathy (CTE), a degenerative brain disease linked to repeated head trauma, according to a study published on August 25, 2023.
The study, conducted by researchers at Mass General Brigham, Boston University, and the Concussion Legacy Foundation, examined 235 donated brains from former NFL players who died during that period. Of those, 215 (91.4%) were diagnosed with CTE. The findings were published in The British Medical Journal.
The study’s lead author, Dr. Daniel Daneshvar, chair of physical medicine and rehabilitation at Mass General Brigham and an associate professor at Harvard Medical School, noted that repeated traumatic brain injuries are a known factor in elevated rates of neurodegenerative disease. He stated that NFL players have about a four times higher rate of death from neurodegenerative disease compared to the general population.
Key findings include:
- 61.3% of former NFL players with CTE met clinical criteria for dementia.
- The majority of head impacts contributing to CTE likely occurred at collegiate, high school, and youth levels, rather than solely in the NFL.
- Researchers emphasized the need for prevention measures to reduce repetitive head impacts across all levels of football.
The NFL issued a statement in response, acknowledging efforts to improve player safety. An NFL spokesperson said the league is “continuously striving to make the game of football safer” through strategies to reduce concussions and head impacts. The statement also highlighted the league’s commitment to providing resources for players’ physical and mental well-being, encouraging former players to seek treatment if concerned about their health.
The study’s authors noted that CTE can only be definitively diagnosed posthumously through brain examination. They added that their findings likely underestimate the true prevalence of CTE among NFL players, as the study only included those who donated their brains. Researchers estimated the actual prevalence could range between 24.5% and 97.7% when accounting for non-donors.
The research drew on data from the UNITE Brain Bank at Boston University, which has examined brains from over 330 NFL players who died between 2008 and 2021. Of those, 93% were diagnosed with CTE.
The study calls for further research into the long-term effects of repetitive head trauma and the development of strategies to mitigate risks at all levels of the sport.