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

ObjectiveTo investigate an effect of smoking cessation on chronic obstructive pulmonary disease (COPD) mortality in Asians.MethodsThe 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.ResultsDuring 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.ConclusionSmoking 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.

► We studied prospectively an effect of smoking cessation on COPD mortality in a large general population.
► Past exposure to cigarettes and other confounding factors have been adjusted.
► Women may be more susceptible to COPD by smoking.
► Long-term smoking cessation reverses the excess risk of COPD mortality.