New Research Puts CTE Rate Among Late NFL Players at 75%

Approximately 75% of former National Football League players who died between 2008 and 2023 likely had chronic traumatic encephalopathy, according to a study published on Wednesday. The research, conducted by a team in Boston and released in Jama Network Open, offers the first broad estimate of CTE prevalence among all deceased ex-players during that period, rather than relying solely on voluntary brain donations.

The analysis examined records for 2,362 former players who averaged five years in the league. While fewer than 400 of these individuals had their brains donated for examination, 93.5% of those donated samples showed physical evidence of the disease. The researchers noted that this rate stands in sharp contrast to the general population, where fewer than 1% of brain samples from community banks contain CTE markers.

Chronic traumatic encephalopathy is characterized by brain atrophy and the accumulation of tau protein, a substance also associated with Alzheimer's disease. The study clarified that the presence of CTE does not guarantee the development of dementia or a decline in cognitive skills. Some individuals with the condition never exhibit noticeable symptoms, while others experience changes in emotional control and behavior, such as depression, memory issues, and severe mood swings.

Despite the high prevalence of brain changes, the researchers estimated that only about 27% of the former players in the analysis had dementia. Yorghos Tripodis, the senior author of the study, addressed the potential impact on the living player community in a statement issued by Mass General Brigham. He acknowledged that the findings might cause concern for current players and their families.

Tripodis added that researchers are standing by to provide support and that there is hope for those living with the condition. He stated that discoveries from brain banks have brought the medical community significantly closer to diagnosing the disease while patients are still alive. Once a definitive diagnosis is possible, the primary focus will shift toward developing effective treatments.

This report follows an earlier study released in August, which determined that at least one in four former NFL players who died between 2016 and 2021 had CTE. Following that previous release, the NFL stated that it continuously strives to make the game safer by implementing strategies to reduce concussions and head impacts. Several high-profile former players, including Junior Seau, Dave Duerson, and Aaron Hernandez, were found to have CTE after their deaths.

The new data reinforces the link between professional football careers and neurodegenerative risk. The study provides a concrete baseline for the frequency of the disease in the player population, distinguishing it from the lower rates observed in the wider community.