We have known that smoking was bad for your heath for at least 100 years. Cigarettes were called coffin nails when I was in grade school in the 1950's. I remember seeing a cartoon that dated back to the 40's that showed the dangers of smoking. Coaches would not let their players smoke because of the health effects. For anyone in the 1960's to say they were unaware cigarettes were harmful meant they had to already be brain dead.
Actually, I quit for two reasons, one (first and foremost) was that I almost burned my infant son's face with a cigarette I had in my mouth when I picked him up and (20), cigarettes went from 35 cents a pack to 50 cents a pack and I thought that was outrageous.