New Study Estimates 75% of Deceased Former NFL Players Had Brain Disease CTE

A recent study published in JAMA Network Open estimates that approximately 75% of former NFL players who died between 2008 and 2023 had evidence of chronic traumatic encephalopathy (CTE). Researchers analyzed records from 2,362 deceased former players to estimate the prevalence of the degenerative brain disease across the entire group, noting that the rate was substantially higher than the less than 1% found in community-based brain banks.

Readers can verify the original findings by reviewing the published paper in JAMA Network Open or checking institutional announcements from Mass General Brigham. Practical implications include increased awareness among living players and families regarding potential neurological health risks, alongside ongoing scientific efforts to develop diagnostic tools and treatments.

Study Methodology and Findings

• Analysis Scope: Researchers examined records for 2,362 deceased former NFL players who averaged five years in the league.
• Brain Donation Subsample: Out of nearly 400 players whose brains were donated for examination, 93.5% showed evidence of CTE.
• General Population Comparison: Study authors reported that fewer than 1% of brain samples in community-based brain banks show CTE evidence.
• Dementia Estimates: Researchers estimated that about 27% of the analyzed former players had dementia.

Symptoms and Pathological Changes

• Physical Indicators: CTE involves brain atrophy and the accumulation of tau protein, which is also associated with Alzheimer's disease.
• Potential Behavioral Effects: The condition can affect areas responsible for emotional control, potentially leading to depression, memory issues, and severe mood changes.
• Asymptomatic Cases: Researchers noted that having CTE-related brain changes does not guarantee that an individual will develop dementia or experience noticeable cognitive decline.

Researcher and League Responses

• Support and Hope: Senior author Yorghos Tripodis acknowledged that the findings may cause concern for living players and their families, emphasizing that support systems and research toward in-life diagnosis are underway.
• NFL Safety Efforts: Following an earlier August study, the NFL stated that it continuously strives to make the game safer by implementing strategies to reduce concussions and head impacts.
• Historical Context: Previous analyses of high-profile former players—such as Junior Seau, Dave Duerson, and Aaron Hernandez—also identified CTE during post-mortem brain examinations.