title: Chronic obstructive pulmonary disease and cognitive impairment in the Chinese elderly population: a large national survey.
abstract: BACKGROUND
  Previous studies suggested an association between chronic obstructive pulmonary disease (COPD) and cognitive impairment, mostly in developed countries. There is no evidence available on the association between these two common chronic disorders in the elderly people in People's Republic of China where the population is aging rapidly.
  
  
  METHODS
  The study population was randomly selected from a nationally representative Disease Surveillance Point System in People's Republic of China. A standardized questionnaire was administered by trained interviewers during a face-to-face interview in the field survey conducted in 2010-2011. Cognitive function was assessed using the Mini-Mental State Examination. COPD was measured by self-report and the Medical Research Council respiratory questionnaire was used to assess respiratory symptoms. A multivariate logistic regression model was applied to examine the association between COPD and cognitive impairment with adjustment for potential confounding factors.
  
  
  RESULTS
  A total of 16,629 subjects aged over 60 years were included in the study. The prevalence of cognitive impairment was 9.4% (95% confidence interval [CI] 7.7, 11.1). Chronic phlegm was associated with significantly higher prevalence of cognitive impairment in models adjusted for age, sex, marital status, geographic region, urban/rural, education, smoking status, alcohol drinking, and indoor air pollution (odds ratio [OR] 1.46, 95% CI 1.11, 1.93). Chronic respiratory symptoms and self-reported COPD were strongly related to cognitive impairment in urban areas. There were no significant effect modifications for sex, regions, educational level, smoking status, and alcohol drinking.
  
  
  CONCLUSIONS
  There was strong association between COPD and cognitive impairment in urban Chinese elderly population.
authors.affiliation: National Center for Chronic and Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China.
authors.forename: Peng
authors.initials: P
authors.lastname: Yin
authors.affiliation: Department of Neurology, Xuanwu Hospital of Capital Medical University, Beijing, People's Republic of China.
authors.forename: Qingfeng
authors.initials: Q
authors.lastname: Ma
authors.affiliation: National Center for Chronic and Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China.
authors.forename: Limin
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Health Education, Qingdao Municipal Center for Disease Control and Prevention, Qingdao, People's Republic of China.
authors.forename: Peng
authors.initials: P
authors.lastname: Lin
authors.affiliation: National Center for Chronic and Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China.
authors.forename: Mei
authors.initials: M
authors.lastname: Zhang
authors.affiliation: National Center for Chronic and Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China.
authors.forename: Shige
authors.initials: S
authors.lastname: Qi
authors.affiliation: National Center for Chronic and Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China.
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Wang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002681:China / Q000453:epidemiology; D003072:Cognition Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D003710:Demography; D015987:Effect Modifier, Epidemiologic; D005260:Female; D006801:Humans; D007361:Intelligence Tests; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D012129:Respiratory Function Tests / Q000379:methods; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology*; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires
keywords: COPD; cognitive impairment; respiratory symptoms