In a study published July 25 in the Journal of the American Medical Medical Association, investigators reported that 177 out 202 brains of deceased American football players showed signs of chronic traumatic encephalopathy or CTE, the degenerative brain disease that's strongly linked to repeated blows to the head. Chronic traumatic encephalopathy (CTE) has been diagnosed in 110 of 111 former NFL players whose brains were donated for research, according to a study published in The Journal of the American Medical Association. Results

Among the 202 deceased brain donors (median age at death, 66 years [interquartile range [IQR], 47-76 years]), CTE was neuropathologically diagnosed in 177 (87%; median age at death, 67 years [IQR, 52-77 years]; mean years of football participation, 15.1 [SD, 5.2]; 140 [79%] self-identified as white and 35 [19%] self-identified as black), including 0 of 2 pre–high school, 3 of 14 high school (21%), 48 of 53 college (91%), 9 of 14 semiprofessional (64%), 7 of 8 Canadian Football League (88%), and 110 of 111 NFL (99%) players. The study has several limitations, including that it is a skewed sample based on a brain donation program because public awareness of a possible link between repetitive head trauma and CTE may have motivated players and their families with symptoms and signs of brain injury to participate in this research. That breaks down to: 110 of 111 (99 percent) NFL players diagnosed with CTE; seven of eight (88 percent) Canadian Football League players; 48 of 53 (91 percent) college football players; 9 of 14 (64 percent) semi-professional players; 3 of 14 (21 percent) high school players; and 0 of two pre-high school players.
A study, published in the Journal of the American Medical Association, finds that 99 percent of the brains donated for scientific research by deceased National Football League players show signs of chronic traumatic encephalopathy (CTE), the disease identified in autopsies of numerous NFL players who have committed suicide, and the subject of the 2015 movie Concussion.