title: European birth cohort studies on asthma and atopic diseases: I. Comparison of study designs -- a GALEN initiative.
abstract: BACKGROUND
  The reasons for the rise in asthma and allergies remain unclear. To identify risk or protective factors, it is essential to carry out longitudinal epidemiological studies, preferably birth cohort studies. In Europe, several birth cohort studies on asthma and atopic diseases have been initiated over the last two decades.
  
  
  OBJECTIVE
  One of the work packages within the Global Allergy and Asthma European Network (GA(2)LEN) project was designed to identify and compare European birth cohorts on asthma and atopic diseases. The present review (part I) describes their objectives, study settings, recruitment process and follow-up rates. A subsequent review (part II) will compare outcome and exposure parameters.
  
  
  METHODS
  For each birth cohort, we collected detailed information regarding recruitment process, study setting, baseline data (pregnancy, birth, parents/siblings) as well as follow-up rates, outcome and exposure parameters at each time point.
  
  
  RESULTS
  We identified and assessed 18 European birth cohorts on asthma, allergic rhinitis and eczema. Six of these studies also focused on food allergies. The birth cohorts were mostly initiated in the 1990s with predominantly urban/metropolitan settings. Many studies were able to maintain high follow-up rates, even after five or more years.
  
  
  CONCLUSIONS
  Due to the unique cooperation within the GA(2)LEN project a common database was established containing study characteristics of European birth cohorts on asthma and atopic diseases. This can be used as a basis for evaluating the possibility to pool data and perform meta-analyses, as well as to recommend criteria for conducting future birth cohorts.
authors.affiliation: Institute for Social Medicine, Epidemiology and Health Economics, Charité, Berlin, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Keil
authors.forename: M
authors.initials: M
authors.lastname: Kulig
authors.forename: A
authors.initials: A
authors.lastname: Simpson
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authors.initials: A
authors.lastname: Custovic
authors.forename: M
authors.initials: M
authors.lastname: Wickman
authors.forename: I
authors.initials: I
authors.lastname: Kull
authors.forename: K C
authors.initials: KC
authors.lastname: Lødrup Carlsen
authors.forename: K H
authors.initials: KH
authors.lastname: Carlsen
authors.forename: H A
authors.initials: HA
authors.lastname: Smit
authors.forename: A H
authors.initials: AH
authors.lastname: Wijga
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authors.initials: S
authors.lastname: Schmid
authors.forename: A
authors.initials: A
authors.lastname: Berg
authors.forename: C
authors.initials: C
authors.lastname: Bollrath
authors.forename: E
authors.initials: E
authors.lastname: Eller
authors.forename: C
authors.initials: C
authors.lastname: Bindslev-Jensen
authors.forename: S
authors.initials: S
authors.lastname: Halken
authors.forename: A
authors.initials: A
authors.lastname: Høst
authors.forename: J
authors.initials: J
authors.lastname: Heinrich
authors.forename: D
authors.initials: D
authors.lastname: Porta
authors.forename: F
authors.initials: F
authors.lastname: Forastiere
authors.forename: B
authors.initials: B
authors.lastname: Brunekreef
authors.forename: U
authors.initials: U
authors.lastname: Krämer
authors.forename: S N
authors.initials: SN
authors.lastname: Willich
authors.forename: U
authors.initials: U
authors.lastname: Wahn
authors.forename: S
authors.initials: S
authors.lastname: Lau
mesh_terms: D000293:Adolescent; D001249:Asthma / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D016208:Databases, Factual; D015340:Epidemiologic Research Design; D005060:Europe; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000453:epidemiology*; D015994:Incidence; D015995:Prevalence