Incidence and risk of chronic obstructive pulmonary disease in a Korean community-based cohort

Ah Young Leem,1 Boram Park,2 Young Sam Kim,1 Ji Ye Jung,1 Sungho Won2 1Division of Pulmonology, Department of Internal Medicine, Institute of Chest Disease, Severance Hospital, Yonsei University College of Medicine, Seoul, 2Department of Epidemiology and Biostatistics, School of Public Health, Seoul National University, Seoul, Korea Purpose: COPD is a leading cause of morbidity and mortality. However, few studies have used spirometry to investigate its incidence, especially in Asia. In the present study, we analyzed the incidence and risk factors of COPD using a community cohort database in Korea. Patients and methods: The study included 6,517 subjects aged 40–69 years from the Ansung–Ansan cohort database I–III (2001–2006). We calculated the crude incidence rate and the standardized incidence rate corrected for the Korean general population and the world population with COPD. We also determined the relative risks (RRs) for incident COPD and the attributable risks. Results: In total, 329 new COPD cases were diagnosed during follow-up. The overall crude incidence rate per 100,000 person-years was 1,447. The standardized incidence rate corrected for the Korean general population was 1,550; this value was higher in men and increased with increasing age. Risk factors for incident COPD were age ≥60 years (adjusted RR [aRR] =2.52 vs age <60 years), male sex (aRR =2.02 vs female), heavy smoking (≥20 pack-years; aRR =2.54 vs never smoker), and lowest income group (first quartile; aRR =2.03 vs fourth quartile). The adjusted attributable risk was highest for education level of high school or lower (44.9%), followed by smoking history (25.8%), income (22.9%), and sex (12.0%). Conclusion: In Korea, 15.5/1,000 people are diagnosed with COPD annually. The incidence rate increases with increasing age, heavier smoking, and decreasing income, with a higher rate in men than in women. Keywords: chronic obstructive pulmonary disease, incidence rate, relative risk, attributable ris