Association between Cigarette Smoking History and Mortality in 36,446 Health Examinees in Korea

Background: It is well known that smoking is a preventable factor for all-cause mortality; however, it isstill questionable how many years after smoking cessation that people will have reduced risk for mortality, inparticular in those with a high interest in their own health. We aimed to examine the association between time sincequitting smoking and total mortality among past-smokers relative to current smokers. Materials and
Methods:We enrolled 36,446 health examinees that voluntarily taken with diverse health check-up packages of high costburden in 1995-2003 and followed them till death by 2004. The history of cigarette smoking consumption wascollected using a self-administrative questionnaire at the first visit time. Mortality risk by smoking cessationyears was analyzed using Cox’s proportional hazard model.
Results: Compared to non-smokers, male smokersover 15 pack-years had higher risk for total mortality (HR=1.49, 95%CI 1.02-2.18). The mortality risk in femalesmokers with same pack-years was more pronounced than that in male smokers (HR=2.83, 95%CI 1.17-7.04)despite a small number of cases. Compared to current smokers, a decrease of total mortality was observed amongthose who ceased smoking, and inverse dose-response was found with years after cessation: RR 0.98 (95%CI,0.64-1.41) (<2 yrs), 0.60 (95%CI, 0.43-0.83) (3-9 yrs), and 0.58 (95%CI, 0.43-0.79) (≥10 yrs).
Conclusions: Areduced risk of total mortality was observed after 3 years of smoking cessation. Our findings suggest that atleast 3 years of smoking cessation may contribute to reduce premature mortality among Asian men.