They wore Washington’s burgundy and gold, endured the punishing collisions of professional football and died decades apart.
Colt Brennan was just 37, Frank Wycheck was 52, and Jake Scott was 75. After their deaths, examinations of their brains revealed the same devastating disease — chronic traumatic encephalopathy, or CTE, a condition that new research estimates were present in nearly three-quarters of deceased NFL players.
A sweeping new study led by researchers at Boston University estimates that nearly three-quarters of former NFL players who died over a 16-year period had CTE, offering disturbing evidence of the neurological damage associated with a sport built on violent collisions and celebrated for its physical punishment.
Published Wednesday, Oct. 28, in JAMA Network Open, the research examined 2,362 former NFL players who died between 2008 and 2023. After correcting for statistical biases that complicated previous research, scientists estimated that 74.5% had CTE at death. Even their most conservative estimate put prevalence at 63.7%.
“With CTE consistently found in less than 1% of donors to community brain banks, an estimated 75% prevalence among NFL players who died over a 16-year period is concerning and suggests we need to increase efforts to support families, diagnose CTE during life, and treat CTE-related symptoms,” lead author Julia Gallini said in a statement.
Brennan, the record-setting University of Hawaii quarterback Washington drafted in 2008, died in 2021. A post-mortem examination revealed Stage I CTE.
Wycheck began his professional career with Washington in 1993 before becoming a three-time Pro Bowl tight end with the Tennessee Titans franchise. He died in December 2023, and Boston University researchers subsequently diagnosed Stage III CTE, indicating more advanced brain pathology.
Scott, a hard-hitting defensive back who won two Super Bowls with the Miami Dolphins before joining Washington in 1976, died in 2020. His autopsy also revealed CTE.
Scientists have struggled for years to determine how common the disease is among former professional football players. Families who witnessed memory loss, confusion, or other cognitive difficulties were more likely to donate a loved one’s brain for examination, potentially exaggerating estimates of CTE throughout the deceased NFL population.
“The wide range reflected uncertainty about how representative brain donors were of the overall NFL population,” Boston University said, referring to an August study that estimated CTE prevalence among deceased former players could range from 25% to 98%. “Brain donors are more likely to have symptoms believed to be related to CTE, a concept known as selection bias.”
Gallini and her colleagues combined federal death records with findings from the Understanding Neurologic Injury and Traumatic Encephalopathy brain bank to account for that problem.
Of 387 donated brains with conclusive examinations, 362 contained evidence of CTE, or 93.5%. Researchers calculated that players with clear cognitive symptoms were about five times more likely to donate their brains than those without such symptoms.
The researchers used that disparity to produce the 74.5% estimate, with a 95% confidence interval ranging from 69.6% to 78.3%. They also estimated that 27.2% of the deceased players had experienced dementia during their lifetimes, although they could not determine how many cases were caused by CTE.
Former NFL quarterback Matt Hasselbeck, an ambassador for the study, spoke about the men who spent their careers absorbing the punishment of professional football.
“It’s hard to learn what the guys who built the game have suffered through,” Hasselbeck said in a statement.
CTE is associated with repetitive head impacts, including collisions that do not necessarily produce diagnosed concussions. The disease can currently be definitively identified only through examination of brain tissue after death.
Researchers cautioned that their estimates apply exclusively to deceased NFL players and cannot determine how many living former players or current Washington Commanders have CTE. Some deceased players may have had early-stage disease without recognizable symptoms.
The NFL said it “continuously strives to make the game of football safer, including by implementing strategies to reduce concussions and head impacts.” The league cited equipment improvements, including Guardian Caps, and rule changes intended to reduce dangerous collisions.
“The NFL remains committed to ensuring that the NFL community has access to a robust – and expanding – set of resources to enhance their physical and mental well-being,” the league said.
The NFL Players Association called the research critical to understanding football’s long-term health consequences and pledged continued investment in scientific studies, medical resources and access to care.
The researchers acknowledged that their calculations depended partly on estimates of cognitive impairment among players whose brains were unavailable for examination. They urged additional investigation into CTE’s progression, symptoms and prevention, particularly among younger athletes.
Hasselbeck, whose 18-year NFL career included three Pro Bowl selections, said the findings demand more than scientific acknowledgment.
“We have to learn from this data to make the game safer, because we can’t accept these numbers for the next generation of players,” he insisted.
