I got a nan, 96, walks to town 3 times a week, still rides her bike, been smoking 60 a day for 40 years, and recently cut back to 40. If i compare her to my other nan 86 frail and pretty much falling apart, now guess which one has had the better lifestyle? the second, very well off always comfortable.
At 96 i think she gets up to keep smoking, and if that keeps her alive then keep doing it.
The centenarian smoker likely was never susceptible to smoking-induced lung cancer in the first place.
male smokers: 17%
female smokers: 12%
nonsmokers: 1%If those numbers are accurate, and entirely due to the effects of smoking (not just other lifestyle behaviors more common with smokers, like drinking) that's easily reason enough to quit. But even in the worst case, the fact remains, most smokers will not get cancer.
You can compute the lifetime risk if you have a prior for the lifetime risk of lung cancer (1% in above example), just by multiplying.
Regardless, smoking increases your overall risk pressure along with all of the other risky choices you can make. It's cumulative with the rest of life's choices.