Or Hockey or Soccer? Concussions are common in many sports, soccer which is considered a "safe" alternative to football has the second highest rate. Also not unlikely to occur in Basketball or Baseball.
The biggest thing for me is the aim of the sport. The aim of American football is to stop the opposing team using your body; soccer and hockey both involve pretty intense strategy to get the ball/puck in the net.
Hockey does have some body-body impact (through checks). I haven't played much hockey, so I don't know how severe it is.
Me personally, I'd rather be the best at creating something.