title: Prevalence of allergic rhinitis among adolescents from Distrito Federal, Brazil: comparison between ISAAC phases I and III.
abstract: OBJECTIVE
  To determine the prevalence of allergic rhinitis in a random group of schoolchildren aged 13 to 14 years in Brasilia, Brazil, to evaluate tendencies over 6 years and to compare prevalence rates among different socioeconomic groups.
  
  
  METHODS
  Two cross-sectional studies were undertaken 6 years apart, using the ISAAC (phases I and III) written questionnaire. Thirty-nine schools were chosen at random from eight administrative regions in Brasilia, and were classified into three groups according to the socioeconomic conditions of the population.
  
  
  RESULTS
  A total of 3,009 questionnaires were collected. Of these 53.5% related to female children and 80% to students from public schools. Prevalence rates for diagnosed rhinitis, recent rhinitis and allergic rhinitis were 20, 29.3 and 12.2%, respectively. Rhinitis was more prevalent in private schools than in public ones (17.8 versus 14.1%) and sufferers were predominantly female. Prevalence rates were also higher among populations with higher socioeconomic status (23.5 versus 12.2%). Comparison with the 1996 data revealed significant increases in the prevalence of diagnosed rhinitis (12.7 versus 20%, p = 0.001). These increases were observed at all socioeconomic levels.
  
  
  CONCLUSIONS
  A large number of 13 and 14-year-old children resident in the Distrito Federal exhibit symptoms indicative of rhinitis and the majority of them have allergic rhinitis. Over a six-year period the prevalence of allergic rhinitis increased significantly, predominantly affecting females and with greater prevalence among students at private school and from families with higher socioeconomic status.
authors.affiliation: Hospital de Base do Distrito Federal, DF, Brazil. wellingtonborges@terra.com.br
authors.forename: Wellington G
authors.initials: WG
authors.lastname: Borges
authors.forename: Dennis Alexander R
authors.initials: DA
authors.lastname: Burns
authors.forename: Maria Luísa B M
authors.initials: ML
authors.lastname: Felizola
authors.forename: Bruno A
authors.initials: BA
authors.lastname: Oliveira
authors.forename: Cejana S
authors.initials: CS
authors.lastname: Hamu
authors.forename: Vanessa C
authors.initials: VC
authors.lastname: Freitas
mesh_terms: D000293:Adolescent; D001938:Brazil / Q000453:epidemiology; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D006255:Rhinitis, Allergic, Seasonal / Q000453:epidemiology*; D012621:Seasons; D012737:Sex Factors; D012959:Socioeconomic Factors; D014505:Urban Population