title: Worldwide variations in prevalence of symptoms of allergic rhinoconjunctivitis in children: the International Study of Asthma and Allergies in Childhood (ISAAC).
abstract: BACKGROUND
  As part of the International Study of Asthma and Allergies in Childhood (ISAAC), prevalence surveys were conducted among representative samples of school children from locations in Europe, Asia, Africa, Australia, North and South America.
  
  
  METHODS
  257,800 children aged 6-7 years from 91 centres in 38 countries, and 463,801 children aged 13-14 years from 155 centres in 56 countries.
  
  
  METHODS
  Written symptom questionnaires were translated from English into the local language for self-completion by the 13-14-year-olds and completion by the parents of the 6-7-year-olds. Rhinitis was described as a problem with sneezing, or a runny, or blocked nose when you (your child) DID NOT have a cold or the flu. Additional questions were asked about rhinitis associated with itchy-watery eyes, interference with activities and a history of hay fever ever.
  
  
  RESULTS
  The prevalence of rhinitis with itchy-watery eyes ("rhinoconjunctivitis") in the past year varied across centres from 0.8% to 14.9% in the 6-7-year-olds and from 1.4% to 39.7% in the 13-14-year-olds. Within each age group, the global pattern was broadly consistent across each of the symptom categories. In centres of higher prevalence there was great variability in the proportion of rhinoconjunctivitis labelled as hay fever. The lowest prevalences of rhinoconjunctivitis were found in parts of eastern Europe, south and central Asia. High prevalences were reported from centres in several regions.
  
  
  CONCLUSIONS
  These results suggest substantial worldwide variations in the prevalence and labelling of symptoms of allergic rhinoconjunctivitis which require further study. These differences, if real, may offer important clues to environmental influences on allergy.
authors.affiliation: Department of Public Health Sciences, St George's Hospital Medical School, London, United Kingdom.
authors.forename: D
authors.initials: D
authors.lastname: Strachan
authors.forename: B
authors.initials: B
authors.lastname: Sibbald
authors.forename: S
authors.initials: S
authors.lastname: Weiland
authors.forename: N
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authors.lastname: Aït-Khaled
authors.forename: G
authors.initials: G
authors.lastname: Anabwani
authors.forename: H R
authors.initials: HR
authors.lastname: Anderson
authors.forename: M I
authors.initials: MI
authors.lastname: Asher
authors.forename: R
authors.initials: R
authors.lastname: Beasley
authors.forename: B
authors.initials: B
authors.lastname: Björkstén
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authors.initials: M
authors.lastname: Burr
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authors.initials: T
authors.lastname: Clayton
authors.forename: J
authors.initials: J
authors.lastname: Crane
authors.forename: P
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authors.lastname: Ellwood
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authors.lastname: Keil
authors.forename: C
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authors.lastname: Lai
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authors.lastname: Mallol
authors.forename: F
authors.initials: F
authors.lastname: Martinez
authors.forename: E
authors.initials: E
authors.lastname: Mitchell
authors.forename: S
authors.initials: S
authors.lastname: Montefort
authors.forename: N
authors.initials: N
authors.lastname: Pearce
authors.forename: C
authors.initials: C
authors.lastname: Robertson
authors.forename: J
authors.initials: J
authors.lastname: Shah
authors.forename: A
authors.initials: A
authors.lastname: Stewart
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authors.lastname: von Mutius
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authors.lastname: Williams
mesh_terms: D000293:Adolescent; D000349:Africa / Q000453:epidemiology; D001208:Asia / Q000453:epidemiology; D001249:Asthma / Q000453:epidemiology*; D002648:Child; D005060:Europe / Q000453:epidemiology; D006801:Humans; D009656:North America / Q000453:epidemiology; D015588:Observer Variation; D015995:Prevalence; D012221:Rhinitis, Allergic, Perennial / Q000453:epidemiology*; D006255:Rhinitis, Allergic, Seasonal / Q000453:epidemiology*; D013020:South America / Q000453:epidemiology