New Study Finds CTE in 25% of Deceased Former NFL Players

A new study shows at least 25% of former NFL players who died from 2016-2021 had CTE, highlighting football's risks.

August 25, 2026

Understanding the Prevalence of CTE in NFL Players

Updated August 25, 2026 at 11:33 AM EDT

New research sheds light on the prevalence of chronic traumatic encephalopathy (CTE) among retired NFL players, a concern that has been the focus of scientific inquiry for years. This latest study, published in The BMJ, by researchers from Mass General Brigham, provides fresh insights into the occurrence of CTE in athletes known for high-impact sports.

With a focus on NFL players who participated in at least one game and passed away between 2016 and 2021, the study uncovered that at least 25% of these athletes were diagnosed with CTE posthumously. Dr. Daniel Daneshvar, the study’s lead author, explained, “We’ve known that this disease process can be caused by, in part, repeated traumatic brain injury. But we didn’t know how common it was.”

CTE, a degenerative brain disease, can only be confirmed through post-mortem brain dissection, leading most studies to rely on brain donations often from individuals who exhibited symptoms. This has complicated understanding its true prevalence, especially among professional athletes in sports like football and ice hockey.

Playing football has long been linked to the brain disease known as CTE, but how prevalent it is is still unknown. A new study of former NFL players who died recently found that at least 25% had CTE.

The study drew from a vast collection of samples at the UNITE Brain Bank at Boston University, where 93% of over 330 donated brains of NFL players showed signs of CTE. The researchers created a comprehensive list of NFL players who had played since 1949 to better understand the sample’s representation in the broader player population.

While the study’s minimum CTE prevalence estimate stands at 25%, the potential maximum could be as high as 97%, if all former NFL players were assumed to have the disease except for those definitively cleared. “The true rate of CTE at death in NFL players is somewhere in the middle,” Daneshvar noted.

The NFL, in a statement to NPR, expressed its commitment to safety improvements, stating the league “continuously strives to make the game of football safer, including by implementing strategies to reduce concussions and head impacts.”

In a statement to NPR, an NFL spokesperson said the league continuously strives to make the game of football safer, including by implementing strategies to reduce concussions and head impacts.

The NFL Players Association emphasized the study as a “sobering reminder” of football’s risks, highlighting the need for continued research and improved support systems for affected players. The correlation between dementia and advanced CTE stages was also examined, with over 90% of Stage IV cases having a dementia diagnosis.

However, further research is necessary to understand the connection between dementia and less severe CTE stages. Rachel Grashow from Harvard’s T.H. Chan School of Public Health stressed the importance of addressing treatable conditions like sleep apnea that may mimic CTE symptoms, to prevent hopelessness among former players.

Some professional players have begun wearing what's called a Guardian Cap in both practice and games. The cap is a soft covering that goes over the existing hard shell of the traditional helmet. The extra padding is thought to provide enhanced protection from heavy hits.

Dr. Randall Chesnut of the University of Washington, who was not part of the study, praised its scope and methodology but noted the cohort’s average age of 66, reflecting careers mostly predating 2005. Changes in NFL regulations and equipment since then may affect current prevalence rates.

According to Nature Medicine, the risk of developing any form of dementia is approximately 42% for Americans over 55, highlighting that neurodegenerative diseases can affect a broader population, not just those with a history of head trauma.

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