12% of Asian American men smoke compared with 2.6% of women. So non smoking Asian women are more likely to live with a smoking man. Could second hand smoking exposure be a factor in this? https://www.lung.org/quit-smoking/smoking-facts/impact-of-to...
There are Many things that cause lung cancer other than smoking. Infact majority of people that smoke don't get Cancer (only about 30% in a group of smokers get lung cancer) Edit: I don't mean it's comforting I prefer to have it at 0/10 I am just trying to say that things that cause cancer are not as deterministic as we think.
However, COPD, once established, is irreversible.
My dad was a long time smoker and it was COPD that eventually got him. He battled it for years after he quit.