Research on 202 former football players found evidence of a brain disease linked to repeated head blows in nearly all of them, from athletes in the National Football League, college and even high school.
It's the largest update on chronic traumatic encephalopathy, or CTE, a debilitating brain disease that can cause a range of symptoms including memory loss.
The report doesn't confirm that the condition is common in all football players; it reflects high occurrence in samples at a Boston brain bank that studies CTE. Many donors or their families contributed because of the players' repeated concussions and troubling symptoms before they died.
It's also uncertain if some players' lifestyle habits — alcohol, drugs, steroids, diet — might somehow contribute, according to Dr. Ann McKee, a Boston University neuroscientist.
McKee said research from the brain bank may lead to answers and an understanding of how to detect the disease in life, "while there's still a chance to do something about it." Currently, there's no known treatment.
CTE was diagnosed in 177 former players or nearly 90 percent of brains studied. That includes 110 of 111 brains from former NFL players; 48 of 53 college players; nine of 14 semi-professional players, seven of eight Canadian Football league players and three of 14 high school players. The disease was not found in brains from two younger players.
The new report was published Tuesday in the Journal of the American Medical Association.