In July 2017, a landmark study found signs of a neurodegenerative disease associated with repeat head trauma in 99% of the brains of 111 deceased former National Football League (NFL) players. Now, researchers have used the results to run calculations ballparking the prevalence of the disease—known as chronic traumatic encephalopathy (CTE)—among all NFL players who were active between 1963 and 2008, the same time as those whose brains were examined in the initial study, Inside Science reports. The risk of eventually developing CTE ranged from about 10% to more than 90%, taking into account the varying degrees of bias in the initial sample, where players exhibiting CTE symptoms prior to their death may have been more likely to donate their brains to the study, the scientists report this week in Neurology. Even the lowest estimated risk is still a serious health issue that NFL and other organizations must consider, the researchers say, as CTE has been associated with symptoms such as cognitive impairment, impulsive behavior, and suicidal thoughts.
