Claim: A new study published in The BMJ found that at least 24.5%, and possibly up to 97.7%, of former NFL players who died between 2016 and 2021 had CTE.
Chronic Traumatic Encephalopathy (CTE) is hardly an unfamiliar subject in the NFL. Given the repeated head impacts and physical nature of the sport, players can face an increased risk of developing the neurodegenerative disease. Over the years, several former NFL players have been suspected of having CTE after their deaths.
Now, a new peer-reviewed study published in The BMJ has examined just how prevalent the condition is among former NFL players who died between 2016 and 2021. The research found that at least 24.5%, and possibly up to 97.7%, of former NFL players who died during that time period suffered from CTE. But is that really the case? Here’s what we found.
Our Verdict: True
The study was conducted by researchers from Mass General Brigham, Harvard Medical School, Boston University’s CTE Center, and other institutions. It was led by Daniel H. Daneshvar, MD, PhD, with Jesse Mez, MD, MS, serving as senior author.
According to the study, CTE can currently only be definitively diagnosed after death through an examination of brain tissue. During the five-year period, 878 former NFL players died, with 235 of them donating their brains for research. Among those whose brains were examined, 215 were found to have CTE, meaning 91.4% of the brain donors had evidence of the disease.
However, researchers cannot conclude that 91.4% of all 878 deceased players had CTE, as the brains of 643 players were not examined. To account for those unexamined players, the researchers calculated a minimum possible prevalence of 24.5%. This assumes that the 215 confirmed CTE cases were the only cases among all 878 former players.
At the other end of the range, the prevalence could be as high as 97.7% if nearly all of the players whose brains were not examined also had the disease.
“Community brain bank studies have shown that CTE affects less than 1 percent of the general population,” lead and corresponding author Daniel Daneshvar, chair of physical medicine and rehabilitation at Mass General Brigham, explained. “To find that somewhere between 24.5 percent and 97.7 percent of NFL players from that time period had this progressive brain disease is a wake-up call for the NFL and scientific communities.”
Therefore, the study concludes that at least 24.5%, or roughly one in four, of the former NFL players who died between 2016 and 2021 had CTE. Interestingly, the study also found that 61.3% of NFL brain donors who had CTE met clinical criteria for dementia, with more severe CTE showing a stronger association with dementia.
Our fact-checking sources:
- The BMG, 25 August 2026. Prevalence of chronic traumatic encephalopathy at death in National Football League players: retrospective population based cohort study, 2008-21
- Harvard Medical School, 25 August 2026. At Least 1 in 4 Former NFL Players Who Died in 2016-2021 Had CTE at Death, Study Finds
- Mass General Brigham, 25 August 2026. At least 1-in-4 former NFL players who died between 2016-2021 had CTE, study finds