title: Prevalence of respiratory and atopic disorders in Chinese schoolchildren.
abstract: BACKGROUND
  Epidemiological surveys have shown that the prevalence of asthma in the Asian population is relatively low. Within the Chinese population, schoolchildren from Hong Kong were found to have the highest rate of asthma.
  
  
  OBJECTIVE
  To compare the prevalence of respiratory and atopic disorders, and to assess the role of atopy in the development of asthma, in Chinese schoolchildren from Hong Kong, Beijing and Guangzhou.
  
  
  METHODS
  Community-based random samples of schoolchildren aged 9-11 years from three Chinese cities (Hong Kong, Beijing and Guangzhou) were recruited for study using the International Study of Asthma and Allergies in Childhood (ISAAC) Phase II protocol. Subjects were studied by parental questionnaires (n = 10902), skin-prick tests (n = 3479) and skin examination (n = 3479).
  
  
  RESULTS
  The prevalence rates of current wheeze, speech limiting wheeze, rhinoconjunctivitis and flexural dermatitis were significantly more common in Hong Kong than in Beijing or Guangzhou. The atopy rate was also higher in Hong Kong (41.2%) than in Beijing (23.9%) or Guangzhou (30.8%). Atopy was strongly correlated with current wheeze (OR 7.74; 95% CI = 5.70-10.51). Subgroup analyses of children from Hong Kong revealed that children born in mainland China who had subsequently migrated to Hong Kong had a significantly lower rate of allergic symptoms and atopy than those children born in Hong Kong.
  
  
  CONCLUSIONS
  Using a standardized written questionnaire along with a skin prick test and skin examination, we confirmed that the prevalence of asthma, allergic diseases and atopy was highest in schoolchildren from Hong Kong. Atopic sensitization is an important factor associated with asthma in Chinese children.
authors.affiliation: Department of Paediatrics, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
authors.forename: G W
authors.initials: GW
authors.lastname: Wong
authors.forename: D S
authors.initials: DS
authors.lastname: Hui
authors.forename: H H
authors.initials: HH
authors.lastname: Chan
authors.forename: T F
authors.initials: TF
authors.lastname: Fok
authors.forename: R
authors.initials: R
authors.lastname: Leung
authors.forename: N S
authors.initials: NS
authors.lastname: Zhong
authors.forename: Y Z
authors.initials: YZ
authors.lastname: Chen
authors.forename: C K
authors.initials: CK
authors.lastname: Lai
mesh_terms: D044466:Asian People; D002648:Child; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000453:epidemiology*; D008297:Male; D015995:Prevalence; D012130:Respiratory Hypersensitivity / Q000453:epidemiology*; D011795:Surveys and Questionnaires