New Study Finds CTE in at Least 1 in 4 Former NFL Players Who Died

A landmark study published in The BMJ has established a striking baseline for chronic traumatic encephalopathy among deceased former NFL players. Researchers found that at least 24.5% of former players who died between 2016 and 2021 had confirmed CTE, providing a deliberately conservative estimate of the disease’s prevalence within this population.

Researchers specifically attempted to address selection bias, one of the biggest limitations surrounding previous CTE research. Families who notice serious neurological or behavioral problems may be more likely to donate a former player’s brain for examination, potentially making brain-bank studies appear to show a higher prevalence than exists across the broader population.

The researchers identified 878 former NFL players who died during the six-year period. Among them, 235 had their brains examined after death, with 215 ultimately diagnosed with CTE. Those confirmed cases alone represented 24.5% of all 878 deceased players identified by researchers, including hundreds whose brains were never examined.

The methodology makes the 24.5% figure particularly significant. For purposes of establishing the minimum prevalence, researchers effectively counted every former player whose brain was not examined as though he did not have CTE. Consequently, the study does not suggest that 24.5% represents the disease’s actual prevalence, but rather a statistical floor.

Because CTE currently requires examination of brain tissue after death for definitive diagnosis, researchers cannot determine how many of the remaining players also had the disease. The study therefore leaves a substantial amount of uncertainty, while demonstrating that confirmed cases already accounted for approximately one-quarter of all former NFL players who died during the period.

Chris Nowinski, a former college football player and co-founder of the Concussion Legacy Foundation who co-authored the research, described the one-in-four finding as a «wake-up call for the NFL and scientific communities.» The results are adding urgency to efforts to understand how years of repetitive head impacts may affect players long after retirement.

Attention is also increasingly turning toward the roughly 20,000 living former NFL players. Researchers and advocates hope improved testing will eventually make it possible to identify CTE during life. Former Pro Bowl quarterback Matt Hasselbeck has joined research efforts seeking better methods of recognizing the disease and neurological risks among living former players.

The findings also give additional weight to testimony from families who watched former players experience profound changes before their deaths. Liz Cross, widow of former NFL cornerback and CBS analyst Irv Cross, has spoken publicly about the depression, mood swings and social withdrawal he experienced before being posthumously diagnosed with stage IV CTE.

Other families have described paranoia, delusions, memory difficulties and emotional instability among former players. Yet one of CTE’s most difficult realities remains unchanged: definitive confirmation still requires post-mortem brain examination. Families can therefore witness years of serious deterioration without knowing whether CTE is responsible until after their loved one has died.

The research arrives against the backdrop of longstanding disputes surrounding football-related neurological injuries. More than 4,500 retired players or their families previously participated in concussion litigation against the NFL, eventually producing a settlement expected to distribute more than $1 billion to qualifying former players suffering from certain neurological conditions.

Researchers are not claiming that one-quarter of everyone who has played in the NFL has CTE. The study specifically examined deceased former players and was retrospective and observational. Its major contribution is establishing a conservative minimum: even assuming every unexamined player was CTE-free, confirmed diagnoses still represented 24.5% of deaths between 2016 and 2021.