title: Risk factors for chronic obstructive pulmonary disease among never-smokers in Korea.
abstract: BACKGROUND
  Chronic obstructive pulmonary disease (COPD) patients include those who have never smoked. However, risk factors other than smoking in never-smokers have not been elucidated sufficiently. This study investigated the risk factors for COPD among never-smokers in Korea using population-based data.
  
  
  METHODS
  The data were retrieved from the Korean National Health and Nutrition Survey IV conducted from 2007 to 2009. Among subjects aged 40 years or older who underwent appropriate pulmonary function tests, never-smokers not diagnosed with asthma and not showing a restrictive pattern on pulmonary function tests were enrolled. Risk factors of COPD in never-smokers were analyzed using logistic regression models.
  
  
  RESULTS
  Among 24,871 participants in the representative Korean cohort, 3,473 never-smokers were enrolled. COPD patients accounted for 7.6% of the never-smokers. In the logistic regression analysis, low education status (odds ratio [OR]: 2.0; 95% confidence interval [CI]: 1.2-3.2), occupational exposure (OR: 2.6; 95% CI: 1.3-5.3), a history of tuberculosis (OR: 4.5; 95% CI: 2.3-8.7), bronchiectasis (OR: 6.0; 95% CI: 1.4-25.4), male sex (OR: 4.2; 95% CI: 2.6-6.7), advanced age (60-69 years vs 40-49 years; OR: 3.8; 95% CI: 2.0-7.0), and being underweight (body mass index <18.5 vs 18.0-24.9 kg/m(2); OR: 3.1; 95% CI: 1.0-9.4) were associated with the development of COPD.
  
  
  CONCLUSIONS
  Low education status, manual labor, a history of tuberculosis and bronchiectasis, as well as male sex, advanced age and being underweight were risk factors for COPD in Korean never-smokers.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, School of Medicine, Ewha Womans University, Seoul, Republic of Korea.
authors.forename: Seok Jeong
authors.initials: SJ
authors.lastname: Lee
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, School of Medicine, Ewha Womans University, Seoul, Republic of Korea.
authors.forename: Seo Woo
authors.initials: SW
authors.lastname: Kim
authors.affiliation: Department of Clinical Trial Center, School of Medicine, Ewha Womans University, Seoul, Republic of Korea.
authors.forename: Kyoung Ae
authors.initials: KA
authors.lastname: Kong
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, School of Medicine, Ewha Womans University, Seoul, Republic of Korea.
authors.forename: Yon Ju
authors.initials: YJ
authors.lastname: Ryu
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, School of Medicine, Ewha Womans University, Seoul, Republic of Korea.
authors.forename: Jin Hwa
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, School of Medicine, Ewha Womans University, Seoul, Republic of Korea.
authors.forename: Jung Hyun
authors.initials: JH
authors.lastname: Chang
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001987:Bronchiectasis / Q000453:epidemiology; D016009:Chi-Square Distribution; D015897:Comorbidity; D005260:Female; D006306:Health Surveys; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000453:epidemiology*; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D012737:Sex Factors; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires; D013851:Thinness / Q000453:epidemiology; D014397:Tuberculosis, Pulmonary / Q000453:epidemiology
keywords: chronic obstructive pulmonary disease; never-smoker; socioeconomic status