About 75% of Former NFL Players Who Died Over 15 Years Had CTE, Study Estimates

BOSTON, Oct. 29 (TodayViralUSA) — About three in four former NFL players who died between 2008 and 2023 likely had chronic traumatic encephalopathy, the degenerative brain disease linked to repeated head impacts, according to a new study that researchers call the first estimate covering every player who died in that period.

The study, led by Boston University researchers with Mass General Brigham and the Concussion & CTE Foundation, was published Wednesday in JAMA Network Open. It put the prevalence of CTE among the 2,362 former players who died during the 15-year span at 74.5%, the highest estimate to date.

Correcting for who donates

CTE can be confirmed only by examining the brain after death, and earlier research relied on brains donated by families, who are more likely to come forward when a player showed symptoms. Among the 387 donated brains evaluated in the new study, 362, or 93.5%, had CTE.

To account for that bias, the researchers combined brain bank data with National Death Index records for all former players who died in the period, including 1,966 who were not donors. They estimated that families of players with cognitive symptoms were about five times more likely to donate, and used that ratio to adjust the donor findings. A more conservative analysis still put the figure at 63.7%.

By comparison, CTE has been found in fewer than 1% of thousands of brains donated to community brain banks in the U.S., Australia, Austria and Brazil, Boston University said.

What the numbers do and don’t show

The researchers estimated that 27.2% of the deceased players had a history of dementia from any cause during life. Not everyone with signs of CTE in the brain develops symptoms, study leader Yorghos Tripodis told NBC News, though he said it is very likely that CTE is driving dementia in this population.

The authors stressed that the estimate applies only to former players who have died and does not predict how many living former players or current players have the disease. An August study from the same group had put the share of players who died between 2016 and 2021 with CTE in a wide range of 25% to 98%.

Dr. Jim Kelly, a neurology professor emeritus at the University of Colorado Anschutz who was not involved in the research, told NBC News the figures remain estimates, noting that far more of the players who died were never autopsied than were.