At least 24.5 percent of former NFL players who died between 2016 and 2021 had chronic traumatic encephalopathy at the time of death, according to a peer-reviewed study published in The BMJ, and the researchers are explicit that the figure is a floor rather than a best estimate.
The study, from Mass General Brigham, Boston University, and the Concussion and CTE Foundation, was published in The BMJ and takes an unusual approach to a persistent measurement problem. CTE can only be confirmed by examining brain tissue after death, so almost every prevalence figure ever published has come from donated brains, and families who donate are more likely to have watched a relative struggle with memory, mood, or behavior.
