title: Skin test reactivity among Danish children measured 15 years apart.
abstract: BACKGROUND
  Knowledge of secular trends in the prevalence of allergy among children stems in large part from questionnaire surveys, whereas repeated cross-sectional studies using objective markers of atopic sensitization are sparse.
  
  
  OBJECTIVE
  To investigate whether the prevalence of skin prick test (SPT) positivity in Danish children has changed from 1986 to 2001.
  
  
  METHODS
  Serial cross-sectional studies of two different random population samples of children aged 7 to 17 years of age, living in urban Copenhagen, Denmark, were performed 15 years apart. The first cohort was investigated in 1986 (n = 527) and the second in 2001 (n = 480). Skin test reactivity to nine common aeroallergens was measured at both occasions.
  
  
  RESULTS
  The prevalence of positive SPT to at least one allergen decreased from 24.1% in 1986 to 18.9% in 2001, (p = 0.05). We found a declining prevalence of sensitization to most allergens tested, statistically significant; however, only for mugwort and Alternaria iridis. Among subjects, who were sensitized to only one allergen, we found significantly fewer individuals with reactions to D. pteronyssinus and mugwort.
  
  
  CONCLUSIONS
  The prevalence of atopic sensitization as judged by SPT positivity has decreased or remained unchanged among Danish children during the 15-year period from 1986 to 2001. The increase in prevalence of allergic disease often reported in comparable studies using questionnaires as sole diagnostic criterion could not be reproduced in this study where objective markers of allergic sensitization were included in the design.
authors.affiliation: Department of Internal Medicine, Bispebjerg Hospital, Copenhagen, Denmark. sft@city.dk
authors.forename: Simon Francis
authors.initials: SF
authors.lastname: Thomsen
authors.forename: Charlotte Suppli
authors.initials: CS
authors.lastname: Ulrik
authors.forename: Celeste
authors.initials: C
authors.lastname: Porsbjerg
authors.forename: Vibeke
authors.initials: V
authors.lastname: Backer
mesh_terms: D000293:Adolescent; D002648:Child; D003430:Cross-Sectional Studies; D003718:Denmark; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000175:diagnosis* / Q000453:epidemiology*; D008297:Male; D015995:Prevalence; D012882:Skin Tests; D013997:Time Factors