Simply put, when you don’t believe in an afterlife — in a spiritual world — you often become obsessed with staying in this world as long as possible. I believe this breeds a deep-seated fear of injury and death and at least partially explains our safety-freak mentality. Jesus said, "And fear ye not them that kill the body, and are not able to kill the soul: but rather fear him that can destroy both soul and body in hell." Without a belief in the soul, the body is all there is. And then the sins against it — smoking, drinking, etc. — become mortal.
Regulating Us to Death | The New American