Objective: Smoking is an important causative factor of chronic obstructive pulmonary disease (COPD), and females are considered more susceptible to the effects of smoking than males. However, in previous Korean studies, the effects of sex differences on the association between smoking and COPD have been controversial. In this study, the effects of sex differences on the association between smoking and COPD and the effects of female hidden smokers on that association in Korean adults were investigated. Methods: Data were acquired from the Korea National Health and Nutrition Examination Surveys (KNHANES). Results: The multivariate logistic regression analysis showed that self-reported smoking status for ex-smoker and current smoker correlated with COPD (odds ratio, OR: 1.67 and OR: 2.41, respectively). Self-reported smoking status for ex-smoker and current smoker correlated with COPD in men (OR: 1.61, OR: 2.43, respectively). Female self-reported current smoking status correlated with COPD (OR: 2.52), but female ex-smoker status was not significantly correlated with COPD. The ratios of cotinine-verified to self-reported smoking rates were 1.95 for women and 1.07 for men. Conclusion: The results of this study were that sex differences might affect the association between COPD and smoking and that female hidden smoking might affect the association between smoking and COPD in Korean adults.
