title: Increased prevalence of chronic obstructive pulmonary disease in a general population.
abstract: BACKGROUND
  Prevalence of COPD is increasing worldwide, and there is need for regularly updated estimates of COPD prevalence and risk factors.
  
  
  METHODS
  In the Norwegian Hordaland County Cohort Study (HCCS), 1664 subjects aged 35-90 yrs answered questionnaires and performed spirometry in 2003-05. We estimated COPD prevalence and analysed risk factors for COPD with logistic regression.
  
  
  RESULTS
  In a previous study phase, prevalence of GOLD-defined COPD was 7%. Eight years later, corresponding prevalence was 14%. Seventy % of the subjects experienced respiratory symptoms. Only 1 out of 4 had a physician's diagnosis. Significant risk factors for COPD were sex, age, smoking habits and pack-years. Men had 1.7 (OR, 95% CI 1.2, 2.3) higher odds for COPD than women. Subjects above 65 yrs had 10.3 (OR, 95% CI 6.4, 16.5) times higher odds for COPD than subjects below 40 yrs. Heavy smokers had 4.2 (OR, 95% CI 2.6, 6.7) times higher odds for COPD than subjects with <10 pack-years. When compared with the previous study phase, age and smoking status had roughly the same associations with COPD prevalence. Educational level and male gender, on the other hand, had less effect on COPD prevalence in 2005 than in 1997, while pack years were more important in 2005 than in 1997.
  
  
  CONCLUSIONS
  Prevalence of GOLD defined COPD has increased from 7% to 14% in nine years. Although the risk factors remain the same, the strength of associations vary. There is still substantial under diagnosis in COPD, and better disease awareness and diagnostic routines are needed.
authors.affiliation: Centre for Clinical Research, Haukeland University Hospital, Bergen, Norway. marie.johanne.waatevik@helse-bergen.no
authors.forename: Marie
authors.initials: M
authors.lastname: Waatevik
authors.forename: Trude Duelien
authors.initials: TD
authors.lastname: Skorge
authors.forename: Ernst
authors.initials: E
authors.lastname: Omenaas
authors.forename: Per Sigvald
authors.initials: PS
authors.lastname: Bakke
authors.forename: Amund
authors.initials: A
authors.lastname: Gulsvik
authors.forename: Ane
authors.initials: A
authors.lastname: Johannessen
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D004522:Educational Status; D005260:Female; D005500:Follow-Up Studies; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology* / Q000209:etiology / Q000503:physiopathology; D012307:Risk Factors; D012720:Severity of Illness Index; D017678:Sex Distribution; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology; D014797:Vital Capacity / Q000502:physiology