title: Prevalence of chronic obstructive pulmonary disease in China: a large, population-based survey.
abstract: BACKGROUND
  The prevalence of chronic obstructive pulmonary disease (COPD) in China is largely unknown.
  
  
  OBJECTIVE
  To obtain the COPD prevalence in China through a large-population, spirometry-based, cross-sectional survey of COPD.
  
  
  METHODS
  Urban and rural population-based cluster samples were randomly selected from seven provinces/cities. All residents 40 years of age or older in the selected clusters were interviewed with a standardized questionnaire revised from the international BOLD (Burden of Obstructive Lung Diseases) study. Spirometry was performed on all eligible participants. Patients with airflow limitation (FEV(1)/FVC < 0.70) were further examined by post-bronchodilator spirometry, chest radiograph, and electrocardiogram. Post-bronchodilator FEV(1)/FVC of less than 70% was defined as the diagnostic criterion of COPD.
  
  
  RESULTS
  Among 25,627 sampling subjects, 20,245 participants completed the questionnaire and spirometry (response rate, 79.0%). The overall prevalence of COPD was 8.2% (men, 12.4%; women, 5.1%). The prevalence of COPD was significantly higher in rural residents, elderly patients, smokers, in those with lower body mass index, less education, and poor ventilation in the kitchen, in those who were exposed to occupational dusts or biomass fuels, and in those with pulmonary problems in childhood and family history of pulmonary diseases. Among the patients who had COPD, 35.3% were asymptomatic; only 35.1% reported lifetime diagnosis of bronchitis, emphysema, or other COPD; and only 6.5% have been tested with spirometry.
  
  
  CONCLUSIONS
  COPD is prevalent in individuals 40 years of age or older in China.
authors.affiliation: Guangzhou Institute of Respiratory Diseases, The First Affiliated Hospital, Guangzhou Medical College, 151 Yanjiang Road, Guangzhou, Guangdong 510120, China.
authors.forename: Nanshan
authors.initials: N
authors.lastname: Zhong
authors.forename: Chen
authors.initials: C
authors.lastname: Wang
authors.forename: Wanzhen
authors.initials: W
authors.lastname: Yao
authors.forename: Ping
authors.initials: P
authors.lastname: Chen
authors.forename: Jian
authors.initials: J
authors.lastname: Kang
authors.forename: Shaoguang
authors.initials: S
authors.lastname: Huang
authors.forename: Baoyuan
authors.initials: B
authors.lastname: Chen
authors.forename: Changzheng
authors.initials: C
authors.lastname: Wang
authors.forename: Diantao
authors.initials: D
authors.lastname: Ni
authors.forename: Yumin
authors.initials: Y
authors.lastname: Zhou
authors.forename: Shengming
authors.initials: S
authors.lastname: Liu
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Wang
authors.forename: Dali
authors.initials: D
authors.lastname: Wang
authors.forename: Jiachun
authors.initials: J
authors.lastname: Lu
authors.forename: Jingping
authors.initials: J
authors.lastname: Zheng
authors.forename: Pixin
authors.initials: P
authors.lastname: Ran
mesh_terms: D000328:Adult; D017677:Age Distribution; D015992:Body Mass Index; D002681:China / Q000453:epidemiology; D003371:Cough / Q000453:epidemiology; D003430:Cross-Sectional Studies; D004391:Dust; D004417:Dyspnea / Q000453:epidemiology; D004522:Educational Status; D005260:Female; D006306:Health Surveys; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects; D010578:Petroleum / Q000009:adverse effects; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology*; D020545:Respiratory Mucosa; D012135:Respiratory Sounds; D012424:Rural Population; D012494:Sampling Studies; D012720:Severity of Illness Index; D017678:Sex Distribution; D012907:Smoking / Q000453:epidemiology; D013147:Spirometry; D014505:Urban Population; D014691:Ventilation
chemical_list: D004391:Dust; D010578:Petroleum