title: Increase in prevalence and severity of asthma in young adults in Copenhagen.
abstract: BACKGROUND
  It is the general impression that the prevalence of asthma has increased during recent decades. A study was undertaken to investigate asthma prevalence, respiratory symptoms, and lung function in young adults in the City of Copenhagen 15 years apart.
  
  
  METHODS
  Men and women aged 20-35 years were sampled from the general population living in a defined area of central Copenhagen. The first examination took place in 1976-8 and comprised 1034 subjects (response rate 67.2%). A new sample comprising 1104 subjects (response rate 62.6%) from exactly the same area was examined 15 years later in 1991-4. All participants answered a questionnaire on respiratory symptoms and diseases and performed spirometric tests with measurement of forced expiratory volume in one second (FEV(1)) and forced vital capacity (FVC).
  
  
  RESULTS
  The prevalence of self-reported asthma increased from 1.5% in the first survey to 4.8% in the second survey (p<0.001). Asthmatic subjects had, on average, poorer lung function than non-asthmatic subjects in terms of FEV(1) and this difference was more pronounced in the second survey than in the first (10.0% of predicted versus 2.4% of predicted). Smoking decreased significantly from 62% in 1976-8 to 45% in 1991-4 (p<0.001).
  
  
  CONCLUSIONS
  The prevalence of self-reported asthma has increased significantly among young adults in Copenhagen over a 15 year period. The severity of asthma, as judged by the level of FEV(1), has also increased. These findings cannot be explained by changes in smoking habits.
authors.affiliation: Department of Respiratory Medicine 223, Hvidovre University Hospital, Hvidovre, Denmark.
authors.forename: E F
authors.initials: EF
authors.lastname: Hansen
authors.forename: Y
authors.initials: Y
authors.lastname: Rappeport
authors.forename: J
authors.initials: J
authors.lastname: Vestbo
authors.forename: P
authors.initials: P
authors.lastname: Lange
mesh_terms: D000328:Adult; D001249:Asthma / Q000453:epidemiology*; D001991:Bronchitis / Q000453:epidemiology; D003718:Denmark / Q000453:epidemiology; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D015995:Prevalence; D012111:Residence Characteristics; D012907:Smoking / Q000453:epidemiology; D014797:Vital Capacity / Q000502:physiology