Health

At least 25% of former NFL players who died between 2016 and 2021 had CTE, study estimates

Researchers at Mass General Brigham established a baseline prevalence rate using CDC death records and brain bank samples.

Updated Aug 25, 2026 · 10:20 UTC1 reports

The short version

A study published in The BMJ found that at least 25% of former NFL players who died between 2016 and 2021 had chronic traumatic encephalopathy (CTE).
Lead author Dr. Daniel Daneshvar stated that 25% represents the low-end baseline, with the true prevalence rate likely falling between 25% and an upper theoretical limit of 97%.
Independent experts noted that the study analyzed players with a mean age of death around 66, meaning most played before modern safety rules and concussion protocols were introduced.
Researchers emphasized the need for living players experiencing cognitive symptoms to seek medical care, noting that treatable conditions like sleep apnea or high blood pressure can mimic CTE symptoms.

Researchers from Mass General Brigham analyzed a denominator list of 1,712 former players who appeared in at least one NFL game and died between 2016 and 2021 using CDC death records and Boston University's UNITE Brain Bank samples.[NPR]
The study established a minimum CTE prevalence rate of approximately 25% among former NFL players who died during the study period.[NPR]
Over 90% of deceased players with Stage IV CTE had been diagnosed with dementia during their lives, but 40% of players whose brains showed no CTE were also diagnosed with dementia.[NPR]
Analysis of death certificates for non-brain donors identified an additional 215 former players whose cause of death included a neurodegenerative disease.[NPR]
An NFL spokesperson stated the league continuously strives to improve safety through impact-reduction strategies and expanding wellness resources for former players.[NPR]

The precise prevalence of CTE among retired NFL players remains unknown, as CTE can currently only be diagnosed post-mortem, though lead researchers estimate the actual rate lies between 25% and 97%.[NPR]
It is unclear whether the study's findings reflect CTE rates for current or recently retired players, given that the study cohort's average age at death was 66 and their careers largely predated modern safety measures.[NPR]