title: Prevalence of physician-diagnosed COPD and its association with smoking among urban and rural residents in regional mainland China.
abstract: OBJECTIVE
  To investigate the prevalence of physician-diagnosed COPD and to explore the relationship between the total amount of cigarettes smoked (TACS) and COPD among urban and rural adults in Nanjing, China.
  
  
  METHODS
  Population-based, cross-sectional study conducted between October 2000 and March 2001.
  
  
  METHODS
  Administrative villages (n = 45) randomly selected from three urban districts and two rural counties of Nanjing municipality, Jiangsu province, China, with an overall population of 5.6 million.
  
  
  METHODS
  All regular local residents >/= 35 years old (n = 29,319), 67.7% from urban areas and 32.3% from rural areas; 49.7% were men and 50.3% were women.
  
  
  RESULTS
  The response rate of potential participants was 90.1%. The overall prevalence of diagnosed COPD was 5.9%. The prevalence of COPD was significantly higher among men than in women (7.2% vs 4.7%, p = 0.000), while the difference between urban and rural participants was not statistically significant (6.7% vs 4.4%, respectively; p = 0.132). The prevalence of COPD was significantly higher among smokers than nonsmokers. After adjusting for age, gender, area of residence, fuels, heating in winter, ventilation in kitchen, passive smoking, education, occupation, average family income, alcohol drinking, cooking oil, body mass index, and physical activity, a dose-response relationship between COPD and TACS was evident in this population (odds ratio [OR], 1.60; 95% confidence interval [CI], 1.34 to 1. 92; OR, 1.39; 95% CI, 1.13 to 1.70; and OR, 1.24; 95% CI, 1.01 to 1.52 for smokers within upper, middle, and lower TACS levels compared with nonsmokers, respectively).
  
  
  CONCLUSIONS
  The overall prevalence of diagnosed COPD (5.9%) among Chinese adults was higher than that (2.5%) estimated by World Health Organization experts, and there was a significant gradient increase in COPD prevalence from the stratum of nonsmokers to the stratum of upper TACS.
authors.affiliation: Nanjing Municipal Center for Disease Control and Prevention, 2 ZiZhuLin, Nanjing, ROC 210003. f_xufei@hotmail.com
authors.forename: Fei
authors.initials: F
authors.lastname: Xu
authors.forename: XiaoMei
authors.initials: X
authors.lastname: Yin
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.forename: HongBing
authors.initials: H
authors.lastname: Shen
authors.forename: LinGeng
authors.initials: L
authors.lastname: Lu
authors.forename: YaoChu
authors.initials: Y
authors.lastname: Xu
mesh_terms: D000328:Adult; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D004736:Energy-Generating Resources; D005260:Female; D005843:Geography; D006801:Humans; D007182:Income; D008297:Male; D008875:Middle Aged; D009790:Occupations; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology* / Q000209:etiology; D012424:Rural Population; D012907:Smoking / Q000009:adverse effects*; D014505:Urban Population