title: Asthma in adolescents--Prevalence trends and associated factors in northeast Brazil.
abstract: BACKGROUND
  Asthma is the most common chronic disease affecting children and adolescents (AD). We evaluated the prevalence of asthma and associated factors in adolescents living in a developing region in northeast Brazil using the ISAAC (International Study of Asthma and Allergies in Childhood) methodology.
  
  
  METHODS
  According to the ISAAC protocol, AD (13-14 year olds, n=3,043 in 2003 and 3,009 in 2011-12) answered the standardised written questionnaire by themselves. In addition, in 2011-12 a random sample of these AD (n=430) also answered a complementary questionnaire (associated factors) and underwent a skin prick test with aeroallergens (Dermatophagoides pteronyssinus, Blomia tropicalis, Blatella germanica, Periplaneta americana, dog dander, cat dander, mixed grass pollen and mixed moulds, including 10mg/mL histamine and negative controls). Data were analysed by univariate and multivariate analysis using Poisson regression.
  
  
  RESULTS
  The prevalence of asthma in 2011-12 in Aracaju was 12.8%, which is lower than that recorded in 2003 (18.7%). Individuals with a dog outside the home (PR=0.93; 95%CI=0.88-0.98; p=0.018) and those with an older sibling (PR=0.94; 95%CI=0.91-0.98; p=0.005) were identified as protective. The presence of smokers in the residence (PR=1.04; 95%CI=1.00-1.09; p=0.039) was associated with an increased risk of developing asthma.
  
  
  CONCLUSIONS
  The prevalence of asthma was significantly lower than the last ISAAC figures reported for Aracaju. Tobacco smoking, a preventable factor, continues to be associated with an increase in the occurrence of asthma and other associations may concur with the hygiene hypothesis.
authors.affiliation: Master in Health Science, Federal University of Sergipe, Aracaju, Brazil. Electronic address: sergioluoli@hotmail.com.
authors.forename: S
authors.initials: S
authors.lastname: Oliveira-Santos
authors.affiliation: University Hospital, Federal University of Sergipe, Aracaju, Brazil.
authors.forename: J
authors.initials: J
authors.lastname: Motta-Franco
authors.affiliation: Department of Statistics, Federal University of Sergipe, Aracaju, Brazil.
authors.forename: I
authors.initials: I
authors.lastname: Barreto
authors.affiliation: Department of Paediatrics, Federal University of São Paulo, São Paulo, Brazil.
authors.forename: D
authors.initials: D
authors.lastname: Solé
authors.affiliation: Department of Medicine, Federal University of Sergipe, Aracaju, Brazil.
authors.forename: R
authors.initials: R
authors.lastname: Gurgel
mesh_terms: D000293:Adolescent; D001249:Asthma / Q000453:epidemiology* / Q000209:etiology; D001938:Brazil / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D016012:Poisson Distribution; D015995:Prevalence; D012307:Risk Factors; D012882:Skin Tests; D011795:Surveys and Questionnaires
keywords: Asthma; ISAAC; Prevalence; Protection, Risk factors; Sensitisation