For some reason—perhaps honoring their late matriarch's idea that she contracted lung cancer from living in Lower Manhattan during 9/11 and breathing toxic air?—Donna Summer's family has released a statement that she was a non-smoker. However, that's not true. I totally believe them if they say she hasn't been a smoker in years and years, but she was obviously a smoker in her youth.
Does the existence of this video mean she got cancer from smoking? Nope. Is there a way to prove she got it from singing in smoky venues? Nope. But I would suggest that it's far more likely she got lung cancer from early smoking, from secondhand smoke or just from a genetic fluke than it is that she got it from 9/11, that's all.
Regardless, hers is a huge and tragic loss and I in no way am suggesting she or any other smokers get what they deserve, just that smoking is never something that has a positive outcome. The best you can hope for is to dodge the high rate of negatives.