Research on 202 former football players found evidence of brain disease in nearly all of them, from athletes in the NFL, college and even high school.
It's the largest update on chronic traumatic encephalopathy, or CTE, a brain disease linked with repeated head blows.
But 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 death.
"There are many questions that remain unanswered," said lead author Dr. Ann McKee, a Boston University...