STUDY ESTIMATES CTE IN 75% OF FORMER NFL PLAYERS WHO DIED

Researchers at Boston University, Mass General Brigham and the Concussion & CTE Foundation estimate that about 75% of former NFL players who died between 2008 and 2023 had chronic traumatic encephalopathy (CTE). CTE is a degenerative brain disease. The researchers examined available death certificates for 2,362 former players who died during that period. They also examined findings from donated brains: researchers identified CTE in 362 of 387 former players whose brains were donated, or about 94%.

The team found that former players who showed symptoms were about five times more likely to have their brains donated than those who did not show symptoms. The researchers used that difference to adjust their estimate for the full group of players who died. Their latest analysis covers more players and a longer period than research some of the same authors published in late August. It also takes account of players whose brains were never donated.

“Many cases may have been early stage at the time of death and possibly symptom free,” the study said. The 75% estimate therefore includes possible cases among players who showed no symptoms before death. The researchers said the expanded approach aimed to produce a more accurate estimate than their earlier work. The finding concerns former NFL players who died during the study period; it does not establish how many living former players have CTE.