The NFL has undoubtedly done its best to cover this up. The most worrying thing is that it is NOT only the concussions themselves that are the problem; it is the 'micro-concussions' that happen in every scrimmage in every game, and in every training session. A football player literally gets hit in the head hundreds of time every year, and it starts at the age of 6 or something.
I really don't think there is too much to be done about this though; the game is extremely violent and brutal in its nature, and that is undoubtedly one of the main reasons behind its popularity. A touchdown gets the loudest noise out of a crowd, but after that it is a massive hit. Can you imagine football without its big tackles? Would anyone want to watch that? Could it even be considered the same sport?