Effects of Smoking Status on Chronic Obstructive Pulmonary Disease Prevalence in Males 40 years and Older: Findings from the Korean National Health and Nutrition Examination Survey

ABSTRACT

BACKGROUND: This is a study of the prevalence of chronic obstructive pulmonary disease (COPD), which shows high mortality worldwide, and the effects of smoking on COPD by using data from the Korea National Health and Nutrition Examination Survey V. METHODS: FEV1/FEV6<0.73 was used as a diagnostic criterion of COPD. Frequency analysis for prevalence, descriptive statistics for general characteristics and ventilation rate according to age-specifications, and complex sample logistic regression analysis for the effect of smoking on COPD prevalence were used. IBM SPSS Statistics 21 Standard, Complex Samples for Medical Science(Windows) was used for data analysis(alpha=0.05). RESULTS: Prevalence of COPD was 11.6+/-0.5% of Koreans in their forties or over, and 17.5+/-0.8% in males, and 6.2+/-0.5% in females. There was significant increase of COPD prevalence with age increment. Before adjusting for age and smoking index(SI), the COPD possibilities of past and current-smokers compared with non-smoking males were (odds ratio [OR] 2.112 [95% confidence interval [CI] 1.551-2.875]) and (OR 1.834 [95% CI 1.319-2.551]) respectively. After adjustments with age and SI, the COPD possibility of current-smoking was 2.099 (1.382-3.188) times higher and for past-smoking was 1.463 (1.012-2.115) times higher than non-smoking. The P-value of each group was significant. The regression coefficients (B) of current-smoking and past-smoking were 0.741 and 0.380 respectively. The prevalence of COPD increased 1.102 (1.090-1.115) times for every 1 year of age increase, and 1.012 (1.007-1.018) times for every 1 SI increase (P<0.001). CONCLUSIONS: After adjusting for age and SI, the prevalence of COPD in smokers was higher than non-smokers. And current-smoking had a higher OR and higher B than past-smoking.