title: Atmospheric pollution and the prevalence of asthma: study among schoolchildren of 2 areas in Rio de Janeiro, Brazil.
abstract: BACKGROUND
  Air pollutants have been associated with the exacerbation of respiratory diseases. They may intensify the inflammatory allergic response and airways reactivity to inhaled allergens. However, it is still not clear if air pollution contributes to the increased prevalence of asthma.
  
  
  OBJECTIVE
  To investigate if different levels of air pollution exposure can be related to differences in the prevalence of asthma.
  
  
  METHODS
  The International Study of Asthma and Allergies in Childhood (ISAAC) protocol was used to determine and compare the prevalence of asthma among schoolchildren in 2 cities of the metropolitan region of Rio de Janeiro, Brazil, Duque de Caxias (DC) and Seropédica (SR), which have different levels of atmospheric pollution. The research involved 4,064 students aged 13 to 14 years from 49 schools in DC and 1,129 from 17 schools in SR. Air pollution was evaluated by the concentration of inhalable particulate matter (PM10).
  
  
  RESULTS
  ISAAC's written questionnaire was answered by 4,040 students aged 13 to 14 years in DC and 1,080 in SR. Between 1998 and 2000, the PM10 annual arithmetic mean was 124 microg/m3 in DC and 35 microg/m3 in SR (acceptable level is up to 50 microg/m3). The prevalence of wheezing ever was 35.1% in DC and 29.9% in SR (P = .001), and the prevalence of wheezing in the last 12 months was 19.0% in DC and 15.0% in SR (P = .002). In DC, 14.5% of the adolescents presented 1 to 3 crises of wheezing in the last year, whereas in SR only 11.0% presented 1 to 3 crises (P = .003).
  
  
  CONCLUSIONS
  In this study, the prevalence of asthma in adolescents was directly related to atmospheric pollution.
authors.affiliation: Division of Immunology, Department of Internal Medicine, Hospital Universitário Clementino Fraga Filho, Faculdade de Medicina, Unversidade Federal do Rio de Janeiro. jlrios@globo.com
authors.forename: José Luiz Magalhães
authors.initials: JL
authors.lastname: Rios
authors.forename: José Laerte
authors.initials: JL
authors.lastname: Boechat
authors.forename: Clemax Couto
authors.initials: CC
authors.lastname: Sant'Anna
authors.forename: Alfeu Tavares
authors.initials: AT
authors.lastname: França
mesh_terms: D000293:Adolescent; D000397:Air Pollution / Q000009:adverse effects*; D001249:Asthma / Q000453:epidemiology*; D001938:Brazil / Q000453:epidemiology; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D015995:Prevalence; D012135:Respiratory Sounds; D011795:Surveys and Questionnaires; D014504:Urban Health / Q000639:trends*