The NY Times admitted the headline is a little sensationalized but the findings are still significant.
"The set of players posthumously tested by Dr. McKee is far from a random sample of N.F.L. retirees. “There’s a tremendous selection bias,” she has cautioned, noting that many families have donated brains specifically because the former player showed symptoms of C.T.E.
But 110 positives remain significant scientific evidence of an N.F.L. player’s risk of developing C.T.E., which can be diagnosed only after death. About 1,300 former players have died since the B.U. group began examining brains. So even if every one of the other 1,200 players would have tested negative — which even the heartiest skeptics would agree could not possibly be the case — the minimum C.T.E. prevalence would be close to 9 percent, vastly higher than in the general population."