title: Increased risk of chronic obstructive pulmonary disease among patients with Helicobacter pylori infection: a population-based cohort study.
abstract: BACKGROUND
  Increasing evidence suggests that Helicobacter pylori infection (HPI) may have extragastric manifestations, including the respiratory system. This study investigated the role of HPI in increasing the subsequent risk of chronic obstructive pulmonary disease (COPD) in a nationwide population.
  
  
  METHODS
  We conducted this retrospective cohort study using data from the Longitudinal Health Insurance Database, which is derived from the Taiwanese National Health Insurance Research Database. A total of 5941 adults who were newly diagnosed with HPI between 2005 and 2006 were selected. Healthy patients without HPI were selected from the general population and frequency matched as a ratio of 4:1, according to age, sex, and index years. Both cohorts were followed up from the index date to the end of 2011 to measure the incidence of COPD. Cox proportional hazard regression analysis was used to assess the hazard ratio (HR) of COPD between the HPI cohort and non-HPI cohorts.
  
  
  RESULTS
  The overall HR of COPD was 1.84 (95% confidence intervals = 1.57-2.17) for the HPI cohort, compared with the non-HPI cohort, after adjusting for age, sex, and comorbidities. Although the incidence of COPD was substantially higher in the elderly participants (age, ≥ 65 years) than that in younger participants, the highest HR (4.05, 95% confidence intervals = 1.39-11.8) of COPD was observed in the youngest (age, 20-49 years) participants.
  
  
  CONCLUSIONS
  In this study, the patients with HPI exhibited a significantly higher risk of COPD than those without HPI did.
authors.affiliation: Department of Respiratory Therapy, China Medical University Hospital, Taichung, Taiwan.|Department of Respiratory Therapy, China Medical University, Taichung, Taiwan.
authors.forename: Yi-Hao
authors.initials: YH
authors.lastname: Peng
authors.affiliation: Department of Gastroenterology, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Cheng-Kuo
authors.initials: CK
authors.lastname: Chen
authors.affiliation: Section of Respiratory Therapy, Taichung Hospital, Ministry of Health and Welfare, Taichung, Taiwan.
authors.forename: Ching-Hua
authors.initials: CH
authors.lastname: Su
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, China Medical University Hospital, Taichung, Taiwan.|Graduate Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan.
authors.forename: Wei-Chih
authors.initials: WC
authors.lastname: Liao
authors.affiliation: Management Office for Health Data, China Medical University Hospital, Taichung, Taiwan.|Graduate Institute of Clinical Medical Science and School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan.
authors.forename: Chih-Hsin
authors.initials: CH
authors.lastname: Muo
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Te-Chun
authors.initials: TC
authors.lastname: Hsia
authors.affiliation: Management Office for Health Data, China Medical University Hospital, Taichung, Taiwan.|Graduate Institute of Clinical Medical Science and School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan.
authors.forename: Fung-Chang
authors.initials: FC
authors.lastname: Sung
authors.affiliation: Department of Microbiology and Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan.|Department of Microbiology and Immunology, Graduate Institute of Biomedical Science, Chang Gung University, Taichung, Taiwan.
authors.forename: Chih-Ho
authors.initials: CH
authors.lastname: Lai
authors.affiliation: Graduate Institute of Clinical Medical Science and School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan.|Department of Nuclear Medicine and PET Center, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Chia-Hung
authors.initials: CH
authors.lastname: Kao
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D015897:Comorbidity; D005260:Female; D016481:Helicobacter Infections / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology; D016480:Helicobacter pylori / Q000302:isolation & purification*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology* / Q000382:microbiology; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods; D013624:Taiwan / Q000453:epidemiology
keywords: chronic obstructive pulmonary disease (COPD) - comorbidity - cohort study - Helicobacter pylori