Key Points
Question  What are the contemporary hazards of cigarette smoking and benefits of quitting smoking by race, ethnicity, and sex among US adults?
Findings  In this prospective cohort study of 551 388 US adults, smoking was associated with appreciably greater all-cause mortality compared with never smoking irrespective of race, ethnicity, or sex. Quitting smoking was associated with a reduction in the excess mortality associated with continued smoking, with larger reductions among those who quit at younger ages.
Meaning  In this study, among men and women from diverse racial and ethnic groups, quitting smoking was associated with large reductions in the excess mortality associated with continued smoking.

https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2797597