The researchers studied the brains of 202 former athletes who had played football in the NFL, the Canadian Football League or at the college or high school level and found signs of CTE in the brains of 110 of the former 111 NFL players.
Of the 111 brains belonging to ex-NFL players, only one showed no trace of CTE upon post-mortem review.
Chronic traumatic encephalopathy (CTE) is a degenerative disease of the brain and is associated with repeated head traumas like concussions.
Released by the American Medical Association, the report diagnosed 177 former players, aged from the National Football League to high school, with some degree of C.T.E.
Researchers still don't know how common it is in football or the general population.
January 2005 - The NFL's Mild Traumatic Brain Injury Committee finds that returning to play after sustaining a concussion "does not involve significant risk of a second injury either in the same game or during the season". The new report was published Tuesday in the Journal of the American Medical Association. "It's like a storm that you can't quite get out of", his wife said. CTE can only be diagnosed postmortem.
Risk of CTE was higher with more years of football playing and with playing at a higher level. "How many years of football is too many?" and "What is the genetic risk?" CTE is often found in people who have endured rehashed head injury.
"This is just a tremendous resource for research", Boston University neuropathologist Ann McKee, a co-author on the study, said in an interview with USA TODAY Sports. A panel of neuropathologists made the diagnosis by examining brain tissue, using recent criteria from the National Institute of Neurological Disorders and Stroke, McKee said.
The evidence is now overwhelming: Football, the most powerful, popular and profitable sport in America, is hazardous to the health of those who play it.
In other words, only former players who exhibited symptoms were tested. "As confirmed by the creators, there are as yet numerous unanswered inquiries identifying with the reason, occurrence and pervasiveness of long haul impacts of head injury, for example, CTE". (Different positions come with different likelihoods of being tackled.) Donors had played football for 15 years, on average. She said he had struggled nearly eight years with frightening symptoms including confusion, memory loss and behavior changes.
"The medical and scientific communities will benefit from this publication and the NFL will continue to work with a wide range of experts to improve the health of current and former NFL athletes", said NFL spokesman Brian McCarthy. Junior Seau, a Hall of Fame linebacker, committed suicide in 2012 and was post-humously diagnosed with a severe case of C.T.E.