title: Asthma cases in childhood attributed to atopy in tropical area in Brazil.
abstract: OBJECTIVE
  This study aimed to explore the association between asthma and atopy in a cohort of children living in a large urban center in Brazil. Atopy was defined by the presence of allergen-specific IgE in serum or by a positive skin prick test.
  
  
  METHODS
  In a sample of 1 445 Brazilian children, the association between the prevalence of asthma, skin prick test positivity, and allergen-specific IgE in serum was investigated.
  
  
  RESULTS
  The prevalence of asthma was 22.6%. The presence of serum allergen-specific IgE was frequent in asthmatics and nonasthmatics, and the prevalence of asthma increased only with levels of allergen-specific IgE > 3.5 kilounits/L. The proportion of asthma attributable to atopy was estimated to be 24.5% when atopy was defined by the presence of allergen-specific IgE. With a given level of specific IgE, no association between skin test reactivity and asthma was observed. Skin prick tests were less sensitive than specific IgE for detection of atopy.
  
  
  CONCLUSIONS
  Most asthma cases in an urban underprivileged setting in Brazil were not attributable to atopy. This observation has important implications for understanding the risk factors for the asthma epidemic in Latin America.
authors.affiliation: Instituto de Saúde Coletiva, Universidade Federal da Bahia, Salvador, Brazil. cunhatmt@hotmail.com
authors.forename: Sergio
authors.initials: S
authors.lastname: Souza da Cunha
authors.forename: Mauricio Lima
authors.initials: ML
authors.lastname: Barreto
authors.forename: Rosemeire Leovigildo
authors.initials: RL
authors.lastname: Fiaccone
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Cooper
authors.forename: Neuza Maria
authors.initials: NM
authors.lastname: Alcantara-Neves
authors.forename: Silvia de Magalhães
authors.initials: Sde M
authors.lastname: Simões
authors.forename: Alvaro Augusto
authors.initials: AA
authors.lastname: Cruz
authors.forename: Laura Cunha
authors.initials: LC
authors.lastname: Rodrigues
mesh_terms: D000485:Allergens / Q000276:immunology; D000818:Animals; D000918:Antibody Specificity; D001249:Asthma / Q000453:epidemiology / Q000209:etiology* / Q000276:immunology; D001938:Brazil / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000150:complications* / Q000453:epidemiology / Q000276:immunology; D007073:Immunoglobulin E / Q000097:blood; D008297:Male; D011204:Poverty Areas; D015995:Prevalence; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012882:Skin Tests; D014329:Tropical Climate; D014505:Urban Population / Q000706:statistics & numerical data
chemical_list: D000485:Allergens; D007073:Immunoglobulin E