New study reveals over 70% of former NFL players may have had CTE
The MCG is set up for its first NFL match ahead at Melbourne Cricket Ground on September 10, 2026 in Melbourne, Australia. Credit: Getty Images/Robert Cianflone
A new study revealed that over 70% of former NFL players may have had chronic traumatic encephalopathy.
According to findings published Wednesday morning by medical journal JAMA Network Open, the estimated prevalence of CTE neuropathology among 2,362 deceased NFL players was 74.5%.
The data, which was analyzed from November 2025 to April 2026, included every NFL player who died between January 2008 and December 2023: 396 brain donors and 1,966 non-donors. The study used Understanding Neurologic Injury and Traumatic Encephalopathy (UNITE) brain bank data and National Death Index records on former NFL players.
CTE can be definitively diagnosed only after death.
“I appreciate the support of NFL families in making this research possible,” said Chris Nowinski, the co-founder and CEO of the Concussion & CTE Foundation and one of the study’s 11 authors. “But the prevalence estimate being so high is unfortunate.”
The study noted that CTE studies are subject to selection bias (or registry bias) with most of the knowledge coming from voluntarily-donated brains, therefore limiting understanding of CTE’s impact. This study’s goal was to estimate the selection-bias-adjusted prevalence.
Nowinski, a former college football player and pro wrestler, said the reason this study is so important is because “a lot of people in football have simply dismissed the high rate of CTE in brain banks by saying it's biased.”
Dr. Rosanna Sabini, DO, the medical director of the Northwell Health Concussion Program, concurred. She said that past studies, such as The Journal of the American Medical Association’s 2017 findings that 110 of the 111 donated former NFL players’ brains showed CTE, had “disproportionate” numbers. The brains had registry bias because families donated them only because they sensed something was wrong.
While Nowinski and his fellow authors could not study the non-donors’ brain data, they could make confident estimates based on their cause of death, age, career length and positions. He said if they died from a neurogenic disease, that would be on their death certificate 30% of the time.
A staggering 93.5% of the players who were brain donors with neuropathologic evaluation had CTE, but adjusting for registry bias decreased the number to 74.5%.
“It is true that people are more likely to give the brain if they notice symptoms in a loved one,” he said. “We estimated they're about five times more likely to give the brain when they notice symptoms in a loved one. But that still leaves a very high prevalence in this community.”
NFL players sustained 168 concussions in 2025, according to The Athletic, an increase from 129 in 2024.
“The NFL continuously strives to make the game of football safer, including by implementing strategies to reduce concussions and head impacts,” the NFL said in a statement. “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. We encourage former players to utilize these resources to identify and seek treatment when they are concerned about their health.”
The league also said it is working with manufacturers to develop “better performing protective equipment,” including Guardian Caps, and that its “top-performing” helmets had a nearly 30% lower concussion rate on-field than its “not recommended” helmets in 2025.
The NFL changed its kickoff rule ahead of the 2024 season to reduce high-speed collisions. It said in February that concussions on kickoffs increased from eight in 2024 to 35 in 2025 “due to the higher number of plays — but the rate remains below the old kickoff format, as the kickoff return rate more than doubled in the second season under the Dynamic Kickoff, resulting in 1,157 more returned kickoffs.”
“Studies like this are critical to improving our understanding of football’s long-term impacts,” the NFL Players Association said in a statement. “The NFLPA remains committed to supporting scientific research, investing in resources that aid players’ physical and mental well-being, and expanding access to care so that they can experience improved health outcomes during and after their playing careers.”
Sabini mentioned that repetitive injuries to the body are not a good thing, of course, and that seems to be accepted everywhere in medicine. But when it comes to the brain and football players (and athletes in other contact-related sports), it’s been a different case.
“A carpenter wears out their arms, shoulders and hands, they have chronic arthritis down the road, and it affects their joints,” she said. “So no one seems to argue about that, but we kind of assume that somehow the brain was immune to this.
“Unfortunately, we never evolved to be woodpeckers, right? We don't have the built-in protection, and so the repetitive hits that contact-related sports endure onto their brain can have risks for developing long-term repetitive injuries to the brain.”
Nowinski hopes that with registry bias factored into Wednesday’s study, people will take the findings more seriously.
“That is the next step of what we have to communicate, is that we can be confident in this estimate,” he said. “We have to change from hoping it's not so bad to accepting it is bad. But there's a lot we can do. We can build the research infrastructure to find a cure for this disease. We can change how we play these sports to reduce the risk for the people currently playing and people playing in the future.
“But it comes from accepting that this problem exists.”
Ben Dickson is Newsday Sports' general assignment reporter. He joined Newsday’s high school sports staff in 2023 after graduating from Maryland, where he covered several of the Terrapins' teams.
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