Haven't read it yet, but a story I read a while back about a kid dying from heart complications, and his parents lobbying to get "Heart Starters" at every game, was educational. Now, kids playing sports have a lot better chance of identifying, and fixing health issues than kids that aren't playing sports.
Most of the injuries and deaths come from health issues that kids were born with, and never knew about. So they're susceptible anyway. They could die from a bicycle crash, a fall, a fight, etc. But since sports are so popular, and tend to garner $$$, they also are more likely to identify health issues.
So IMHO, kids should never stop playing sports, as long as they appear healthy. Otherwise, you might as well lock them in their rooms with a video game and watch them die from a weakened immune system, poor heart health, or obesity.
A child's body is a body in training. Some people "babysit" their kids with food and a television. So they're going to have issues.
It's the parents that are involved with their kids, the ones that get them in to activities outside of school hours (doesn't have to be sports), that are training their children's bodies to be active and healthy. That "Training' is going to follow their children throughout life, and make their experiences more enjoyable, and healthier.