Study Finds At Least One in Four NFL Players Develop CTE

A recent study estimates that at least one in four former National Football League (NFL) players had chronic traumatic encephalopathy (CTE) at the time of their death, a degenerative brain disease linked to repeated head trauma, according to research published in 2026.

The study examined 878 former NFL players who died between 2016 and 2021, finding that 215—approximately 24.5 percent—had CTE confirmed through brain examination after death, as reported by The New York Times and CBC News.

Researchers noted that the actual prevalence could be higher since 643 brains from the cohort were not examined, and many may have had the disease as well.

CTE, a progressive neurological condition, can only be definitively diagnosed postmortem. It is associated with repeated impacts to the head, commonly sustained in contact sports like football. The disease causes symptoms ranging from severe memory loss and balance issues to major personality changes, including depression and aggression.

Lead author Dr. Daniel Daneshvar, chair of Physical Medicine and Rehabilitation at Mass General Brigham and associate professor at Harvard Medical School, said, "We were unfortunately both surprised but saddened to see that the minimum rate was so alarmingly high."

He further explained that among brain donors with CTE, about 60 percent met the clinical criteria for dementia, suffering impairments so severe they could not manage daily activities such as grooming or feeding themselves.

"They had clinical impairment in their thinking and memory that was so severe they couldn't take care of their own activities of daily living," Daneshvar said.

Canadian neuroscientist Dr. Charles Tator, emeritus scientist at the University Health Network's Krembil Brain Institute, described the findings as "another wake-up call" to increase attention to brain safety in sports.

He pointed out that while the NFL has introduced measures to better protect players, such as reducing dangerous tackles and allowing extra protective gear, more awareness is needed regarding the long-term consequences of cumulative head impacts.

"The cumulative force to the head that someone experiences over their life has long-term consequences," Daneshvar said, emphasizing the importance of preventive actions across all contact sports, not just focusing on concussions.

Tator highlighted the importance of early prevention, referencing Ontario's concussion prevention law, Rowan's Law, which sets strict protocols for removing athletes from sport after head injuries, a measure not yet widely adopted elsewhere.

Former Canadian Football League player Tim Fleiszer, head of the Concussion Legacy Foundation, called for reducing repetitive head impacts in youth sports, suggesting eliminating heading in youth soccer practices as a significant preventive step.

Neurologist Dr. Matthew Burke from Sunnybrook Health Sciences Centre noted that while the study's retrospective design has limitations, the findings should encourage discussion about brain health as football preseason approaches.