Originally Posted by
ScottCommutes
Thanks! That is a study of a quarter of a million people. Good for safety/advocacy but also highly pertinent to commuting. I have no idea how riding a bike reduces your risk of cancer. They even assert that the health benefits of cycling outweigh the risks of riding in traffic. Still seems possible, however, that healthier people self-select to do active commuting, which makes sense intuitively.
Or less-healthy people self-select to avoid exertion. ("Why are you growing a beard?" "I'm not doing anything; you're shaving.")