title: The analyses of risk factors for COPD in the Li ethnic group in Hainan, People's Republic of China.
abstract: OBJECTIVE
  To study the risk factors for chronic obstructive pulmonary disease (COPD) in Li population in Hainan province, People's Republic of China.
  
  
  METHODS
  Li people above 40 years of age from Hainan were chosen by stratified random cluster sampling between 2012 and 2014. All participants were interviewed with a home-visiting questionnaire, and spirometry was performed on all eligible participants. Patients with airflow limitation (forced expiratory volume in 1 second [FEV1]/forced vital capacity [FVC] <0.70) were further examined by postbronchodilator spirometry, and those with a postbronchodilator FEV1/FVC <0.70 was diagnosed with COPD. The information of physical condition and history, smoking intensity, smoking duration, second-hand smoking, education, job category, monthly household income, working years, residential environment, primary fuel for cooking and heating (biomass fuel including wood, crop residues, dung, and charcoal, or modern fuel such as natural gas, liquefied petroleum gas, electricity, and solar energy), ventilated kitchen, heating methods, air pollution, recurrent respiratory infections, family history of respiratory diseases, cough incentives, and allergies of COPD and non-COPD subjects was analyzed by univariate and multivariate logistic regression models to identify correlated risk factors for COPD.
  
  
  RESULTS
  Out of the 5,463 Li participants, a total of 277 COPD cases were identified by spirometry, and 307 healthy subjects were randomly selected as controls. Univariate logistic regression analyses showed that older people (65 years and above), low body mass index (BMI), biomass smoke, 11-20 and >20 cigarettes/day, smoking for 40 years or more, second-hand smoking, recurrent respiratory infections, and induced cough were risk factors for COPD, whereas high BMI, high education level, and presence of ventilated kitchen were protective factors. Subsequent multivariate logistic regression model further demonstrated that aging, low BMI, biomass smoke, >20 cigarettes/day, and recurrent respiratory tract infections were high-risk factors for COPD in the Li population.
  
  
  CONCLUSIONS
  The incidence of COPD has a strong correlation with age, BMI, biomass smoke, >20 cigarettes/day, and recurrent respiratory infections, suggesting they were high-risk factors for COPD in Li population.
authors.affiliation: Department of Emergency, People's Hospital of Hainan Province, Haikou, Hainan, People's Republic of China.
authors.forename: Yipeng
authors.initials: Y
authors.lastname: Ding
authors.affiliation: Department of Respiratory, The Third People's Hospital of Haikou, Haikou, Hainan, People's Republic of China.
authors.forename: Junxu
authors.initials: J
authors.lastname: Xu
authors.affiliation: Department of Emergency, People's Hospital of Hainan Province, Haikou, Hainan, People's Republic of China.
authors.forename: Jinjian
authors.initials: J
authors.lastname: Yao
authors.affiliation: Department of Respiratory, The Third People's Hospital of Haikou, Haikou, Hainan, People's Republic of China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Emergency, People's Hospital of Hainan Province, Haikou, Hainan, People's Republic of China.
authors.forename: Ping
authors.initials: P
authors.lastname: He
authors.affiliation: Department of Emergency, People's Hospital of Hainan Province, Haikou, Hainan, People's Republic of China.
authors.forename: Yanhong
authors.initials: Y
authors.lastname: Ouyang
authors.affiliation: Department of Emergency, People's Hospital of Hainan Province, Haikou, Hainan, People's Republic of China.
authors.forename: Huan
authors.initials: H
authors.lastname: Niu
authors.affiliation: Department of Emergency, People's Hospital of Hainan Province, Haikou, Hainan, People's Republic of China.
authors.forename: Zhongjie
authors.initials: Z
authors.lastname: Tian
authors.affiliation: Department of Emergency, People's Hospital of Hainan Province, Haikou, Hainan, People's Republic of China.
authors.forename: Pei
authors.initials: P
authors.lastname: Sun
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D044466:Asian People; D015992:Body Mass Index; D002681:China / Q000453:epidemiology; D005260:Female; D005541:Forced Expiratory Volume; D006304:Health Status; D006306:Health Surveys; D006798:Housing; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008168:Lung / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009765:Obesity / Q000175:diagnosis / Q000208:ethnology; D016017:Odds Ratio; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000208:ethnology* / Q000503:physiopathology; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects / Q000208:ethnology; D012959:Socioeconomic Factors; D013147:Spirometry; D011795:Surveys and Questionnaires; D014797:Vital Capacity
keywords: Li population; chronic obstructive pulmonary disease; epidemiology; survey