title: Prevalence of asthma in Portugal - The Portuguese National Asthma Survey.
abstract: BACKGROUND
  Asthma is a frequent chronic respiratory disease in both children and adults. However, few data on asthma prevalence are available in Portugal. The Portuguese National Asthma Survey is the first nationwide study that uses standardized methods. We aimed to estimate the prevalence of current asthma in the Portuguese population and to assess the association between 'Current asthma' and comorbidities such as upper airways disease.
  
  
  METHODS
  A cross-sectional, population-based, telephone interview survey including all municipalities of Portugal was undertaken. Participants were randomly selected to answer a questionnaire based on the Portuguese version of the GA2LEN survey. 'Current asthma' was defined as self-reported lifetime asthma and at least one of 3 symptoms in the last 12 months: wheezing, waking with breathlessness or having an asthma attack.
  
  
  RESULTS
  Data were obtained for 6 003 respondents, with mean age of 38.9 (95%CI 38.2-39.6) years and 57.3% females. In the Portuguese population, the prevalence of 'Current asthma' was 6.8% (95%CI 6.0-7.7) and of 'Lifetime asthma' was 10.5% (95%CI 9.5-11.6) Using GA2LEN definition for asthma, our prevalence estimate was 7.8% (95%CI 7.0-8.8). Rhinitis had a strong association with asthma (Adjusted OR 3.87, 95%CI 2.90-5.18) and the association between upper airway diseases and asthma was stronger in patients with both rhinitis and sinusitis (Adjusted OR 13.93, 95%CI 6.60-29.44).
  
  
  CONCLUSIONS
  Current asthma affects 695 000 Portuguese, with a prevalence of 6.8%. People who reported both rhinitis and sinusitis had the highest risk of having asthma.
authors.affiliation: Center for Research in Health Technologies and Information Systems, Faculdade de Medicina da Universidade do Porto, Porto, Portugal. jfonseca@med.up.pt.
authors.forename: Ana
authors.initials: A
authors.lastname: Sa-Sousa
authors.forename: Mário
authors.initials: M
authors.lastname: Morais-Almeida
authors.forename: Luis Filipe
authors.initials: LF
authors.lastname: Azevedo
authors.forename: Rosa
authors.initials: R
authors.lastname: Carvalho
authors.forename: Tiago
authors.initials: T
authors.lastname: Jacinto
authors.forename: Ana
authors.initials: A
authors.lastname: Todo-Bom
authors.forename: Carlos
authors.initials: C
authors.lastname: Loureiro
authors.forename: António
authors.initials: A
authors.lastname: Bugalho-Almeida
authors.forename: Jean
authors.initials: J
authors.lastname: Bousquet
authors.forename: João Almeida
authors.initials: JA
authors.lastname: Fonseca