New Model Shows 75% of Deceased Ex-NFL Players Likely Had CTE

A team of Boston-based researchers estimated that approximately 75% of former National Football League players who died between 2008 and 2023 exhibited signs of chronic traumatic encephalopathy. The study, published in JAMA Network Open on Wednesday, marks the first effort to project CTE rates across the entire population of deceased ex-players rather than limiting the analysis to those who donated their brains for examination.

The analysis relied on records for 2,362 men who spent an average of five years in the NFL. Of that group, nearly 400 had their brains examined by scientists. The physical markers for CTE were present in 93.5% of those donated specimens. The researchers contrasted this figure with community brain banks, where fewer than 1% of samples show evidence of the condition.

CTE is a degenerative disease characterized by brain atrophy and the accumulation of tau protein, a substance also associated with Alzheimer's disease. The study notes that while the protein buildups are present in the majority of ex-players, they do not guarantee that a person developed dementia or suffered a decline in cognitive function during life.

The authors estimated that about 27% of the former players in the dataset had dementia. The condition can also impact emotional regulation and behavior, leading to symptoms such as depression, memory issues, and severe mood swings. The financial and medical implications for the league's workforce remain a focus as the player population ages.

Yorghos Tripodis, the study's senior author, said the findings may cause concern for living players and their families. He stated that researchers are standing by to provide support and that the work brings the medical community closer to diagnosing CTE in living individuals. The primary goal moving forward is developing effective treatments for those identified with the condition.

The NFL responded to a similar August study, which found that at least one in four former players who died between 2016 and 2021 had CTE. The league said it continuously strives to make the game safer by implementing strategies to reduce concussions and head impacts. High-profile former players who died by suicide, including Junior Seau, Dave Duerson, and Aaron Hernandez, were confirmed to have had CTE after post-mortem examinations.