Estimating the prevalence at death of CTE neuropathology among professional football players.

In July 2017, JAMA published results from autopsies of the brains of 202 deceased American football players.1 Of the 111 participants who had played in the National Football League (NFL), 110 (99%) received a neuropathologic diagnosis of chronic traumatic encephalopathy (CTE), a progressive neurodegenerative disease associated with head trauma. This 99% figure received substantial media coverage when the study was published.