Study: CTE Found in 215 of 235 Donated Brains From Former NFL Players

Former NFL players who donated their brains after death between 2016 and 2021 showed chronic traumatic encephalopathy in 215 of 235 cases, according to research published by Mass General Brigham, Boston University and the Concussion + CTE Foundation. The finding sharpens attention on cumulative head trauma that begins long before professional careers.

The 235 brains came from 878 former players who died in that period. Researchers reported that repeated traumatic brain injuries correlate with higher rates of neurodegenerative disease, including a fourfold increase in deaths from those conditions compared with the general population, said lead author Daniel Daneshvar of Mass General Brigham and Harvard Medical School. Dementia appeared frequently among the donors.

Daneshvar noted that most head impacts occur outside the NFL. He said the bulk took place at college, high school and youth levels, where contact practices remain more frequent. The same study recorded lower all-cause mortality among NFL players than in the general population, a result included in the institutions’ accompanying press materials.

An NFL spokesperson stated the league continues to reduce concussions and head impacts while expanding resources for physical and mental health. Daneshvar urged athletes with cognitive symptoms to consult specialists in neurodegenerative disease and called for limits on contact practices at every level of the sport.

High-profile cases such as Junior Seau, Dave Duerson and Aaron Hernandez previously linked CTE to former players who died by suicide. The 2011 NFL collective bargaining agreement cut contact practices, and the Ivy League later banned full-contact tackling in practices. The Supreme Court in 2016 allowed the league’s concussion settlement with retired players to proceed.