I always try to be as safe as I can. Wear a respirator when grinding. Have plenty of ventilation. I recently have been wearing a respirator when I am welding. I think taking the necessary steps to be safe lower your chances for having future health problems.
My grandmother lived a very healthy life. Never smoked, I never remember her drinking, ate healthy, and exercised. She died of cancer at age 75. Her mother lived to be in her early 90’s and smoked her whole life. Actually she quite smoking 2 years before she died.
I know of a guy who must be almost 80 now and he has smoked and drank his whole life. He also did auto body work his entire career. He never wore a respirator for anything, painting, or sanding bondo. His son told me that he would finish painting a car and come out of the paint booth blow his nose and it would always be the color of the car that he painted. In my opinion he is extremely lucky, but it just goes to show you that you never know how things are going to work out.