In addition to the 111 brains from those who played in the N. .L., researchers also examined brains from the Canadian Football League, semi-professional players, college players and high school players. Of the 202 brains studied, 87 percent were found to have C.T.E. The study found that the high school players had mild cases, while college and professional players showed more severe effects. But even those with mild cases exhibited cognitive, mood and behavioral symptoms.
There is still a lot to learn about C.T.E. Who gets it, who doesn’t, and why? Can anything be done to stop the degeneration once it begins? How many blows to the head, and at what levels, must occur for C.T.E. to take hold?
“It is no longer debatable whether or not there is a problem in football — there is a problem,” Dr. McKee said.
Would seem it starts at the lowest levels of the game and just continues to grow worse as the players progress into college and then the pros.
Don't see how I could ever even consider letting my son play on any level. The risks are simply not worth the rewards.