At Least One in Four Former NFL Players Who Died Between 2016 and 2021 Had the Progressive Brain Disease CTE, Study Suggests

The true prevalence of the neurodegenerative disease—which is associated with repeated head injuries—among the deceased football players might be much higher. CTE affects other athletes too, including hockey players, soccer players and wrestlers

Sarah Kuta | Daily Correspondent

August 27, 2026 10:00 a.m.

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At least a quarter of former professional football players who died between 2016 and 2021 had chronic traumatic encephalopathy, or CTE, a progressive, degenerative brain disease, according to a study published on August 25 in the British Medical Journal. The true prevalence of CTE among the deceased NFL players might be much higher.

Those with first-hand experience agree. “I bet the real number is a lot bigger,” Randy Grimes, a 66-year-old former NFL athlete who played for the Tampa Bay Buccaneers from 1983 to 1992, tells the New York Times’ John Branch.

CTE is believed to be caused by repeated head injuries, such as those endured in contact sports like football, hockey, soccer, wrestling and martial arts. Symptoms like memory loss and mood swings can hint that someone might have CTE. However, the disease can only be diagnosed after death during an autopsy, when pathologists look for specific physical changes in the brain associated with CTE.

CTE was first diagnosed in a former NFL player in 2005. Since then, it’s been confirmed via autopsy in more than 300 athletes who were previously in the league. However, until now, researchers hadn’t been able to determine how widespread the disease might be—in other words, how common is it?

To figure that out, scientists considered the 1,712 former NFL players—individuals who participated in at least one NFL game—who died between 2008 and 2021, 338 of whom had their brains donated for research purposes. However, these organs could create a skewed sample, since families might be more likely to donate brains of athletes who experienced cognitive problems and therefore had CTE.

So, the team zoomed in on former player deaths between 2016 and 2021, when brain donation was most frequent. Of the 878 individuals who died during that period, 235 had their brains donated for analysis, and 215 were found to have CTE. Special statistical methods helped the researchers account for the unstudied brains and potentially skewed sample of analyzed brains, yielding an estimated CTE prevalence range.

At a minimum, 24.5 percent of players who died during the study period had CTE, and at a maximum, 97.7 percent had the disease, the researchers calculated. The true prevalence probably falls somewhere in the middle. For comparison, past research has found that CTE affects less than 1 percent of the general population.

The new work is “significant,” says Randall Chesnut, a neurological surgeon at the University of Washington who wasn’t involved in the study, to NPR’s Becky Sullivan. “It’s really well done. It’s a large population. It’s well controlled within the limits of the statistical analysis that they can pull off on this.”

The findings should serve as a “wake-up call” for the NFL, lead author Daniel Daneshvar, a physician at Mass General Brigham and a brain injury researcher at Harvard Medical School, says in a statement.

Still, Grimes tells the Times that many NFL players shy away from discussing CTE, even though they or their teammates may already have it.

“We probably could move forward faster in our research if we did talk more about it,” says Grimes, who runs a nonprofit that counsels retired athletes. “But players don’t want to do it. They don’t want to think they have it; they don’t want to think they’re seeing it. Deep down, we all know that probably the majority of us are going to have some form of CTE.”

Although there’s no way to reverse the brain damage, physicians can help people with suspected CTE manage their symptoms and improve their quality of life.

The NFL has taken steps to improve player safety in recent years, including banning dangerous plays, changing rules, implementing concussion protocols, supporting advances in helmet technology and requiring some player groups to wear soft-shell helmet covers during contact practices.

In a statement shared with NPR in response to the new study, an NFL spokesperson said the league “continuously strives to make the game of football safer” and “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 NFL Players Association, the union that represents professional football players, wrote in an email to players and player agents that the study was “a sobering reminder that football carries real risks, and those risks can have lasting consequences for players and their families.” The findings should serve as a “call to action across the entire football ecosystem.”

“While we have learned a great deal over the past two decades, there is more work to do,” the association wrote.

Daneshvar echoed that sentiment, telling WBUR’s Priyanka Dayal McCluskey that more needs to be done to protect football players at every level of the sport. There is no cure for CTE. But scientists know how to prevent it, he says.

“We know that the head impacts that these athletes experienced do not only occur at the NFL level,” he says. “They also occurred at the college level, the high school level, in some cases the youth level. And all of those cumulative hits to the head, the cumulative force of those hits to the head—that’s what drives the risk of this disease process. So, we need to be better at mitigating and eliminating the unnecessary g-force to the head that athletes experience.”

Sarah Kuta is a writer and editor based in Longmont, Colorado. She covers history, science, travel, food and beverage, sustainability, economics and other topics.