Smoking cessation and COPD mortality among Japanese men and women: The JACC study

Objective: To investigate an effect of smoking cessation on chronic obstructive pulmonary disease (COPD) mortality in Asians. Methods: The data was obtained from the Japan Collaborative Cohort Study for Evaluation of Cancer Risk (JACC Study). A total of 41465 Japanese men and 52662 Japanese women aged 40-79. years who had no history of COPD, asthma, other chronic lung diseases, cardiovascular disease or cancer were followed between 1988 and 2008. Results: During median 18-year of follow-up, there were 285 (251 men and 34 women) documented deaths from COPD. Multivariable-adjusted hazard ratios with 95% confidence intervals of COPD death were 4.46 (2.72-7.29) and 9.26 (4.19-20.5), respectively for current male and female smokers when compared to never smokers. Compared with current smokers, the multivariable HRs for 5-9. years and 10. years or more smoking cessation prior to baseline were 0.44 (0.22-0.87) and 0.36 (0.22-0.58) in men, respectively while the HR for never smokers was 0.30 (0.16-0.57). There were an insufficient number of COPD deaths in women to clarify this association. Conclusion: Smoking cessation for ten years or more prior to enrollment reverses the excess risk of COPD mortality to a level similar to that observed among never smokers in men.