Study estimates CTE in 74.5% of deceased former NFL players

A Boston University-led study estimates that 74.5% of former NFL players who died from 2008 through 2023 had chronic traumatic encephalopathy (CTE) pathology, after adjusting for the likelihood that symptomatic players’ families were more likely to donate their brains for research. The analysis covered 2,362 former players who died during the 16-year period. Researchers examined donated brain tissue from 387 of them; 362, or 93.5%, showed CTE pathology. The team used death records and information about players’ symptoms to estimate how donation patterns affected the results, bringing the estimated prevalence across the full group to 74.5%. Researchers estimated that families of players who had cognitive symptoms were about five times more likely to donate a brain than families of players without those symptoms. That difference can make studies based only on donated brains overstate how common CTE is among a broader population. The new estimate is a statistical adjustment, not a direct examination of every player in the cohort. The findings, published in JAMA Network Open, apply to deceased former NFL players in the specified period. They do not establish how common CTE is...