By Ahmed Abdelsalam
A new study published Wednesday estimates that about 75% of former NFL players who died between 2008 and 2023 had evidence of chronic traumatic encephalopathy (CTE), a degenerative brain disease linked to repeated head trauma.
Study Details and Methodology
The research, published in JAMA Network Open and conducted by a Boston-based team, analyzed records from 2,362 deceased former NFL players who spent an average of five years in the league. Of nearly 400 players whose brains were donated for examination, 93.5% showed evidence of CTE.
Comparison with General Population
The study represents the first attempt to estimate CTE prevalence among all former NFL players who died during the 15-year period, rather than limiting analysis to brain donors. Researchers said the estimated rate was substantially higher than in the general population, where less than 1% of community-based brain bank samples contain CTE evidence.
Dementia and Symptom Estimates
Physical changes associated with CTE include brain atrophy and accumulations of tau protein, also seen in Alzheimer’s disease. However, the presence of CTE-related changes does not guarantee dementia or cognitive decline; some individuals may never develop noticeable symptoms. Researchers estimated approximately 27% of the former players in the analysis had dementia.
Researchers' Comments and Support
CTE can also damage brain areas responsible for emotional control and behavior, with potential symptoms including depression, memory problems, severe mood changes, and other behavioral difficulties. “We recognize these findings may cause concern for the community of living players and their families,” said Yorghos Tripodis, the study’s senior author, in a statement released by Mass General Brigham. “We want them to know that we and others are standing by to provide support, and that we have hope for those living with CTE.”
Tripodis added that discoveries from the brain bank have brought researchers significantly closer to a diagnosis during life, at which point the most important goal will be to develop effective treatments for CTE.
NFL Response and High-Profile Cases
The findings follow an August study that determined at least one in four former NFL players who died between 2016 and 2021 had CTE. In response to that earlier study, the NFL stated it continuously strives to make football safer, including implementing strategies to reduce concussions and head impacts.
High-profile NFL players who died by suicide — including Junior Seau, Dave Duerson, and Aaron Hernandez — were found to have had CTE when their brains were analyzed after death.
