title: Environmental factors associated with childhood eczema: Findings from a national web-based survey.
abstract: BACKGROUND
  Genetic and environmental factors are known to be related to the development of childhood eczema. Our aim was to assess the environmental factors associated with the prevalence of eczema among children using a web-based survey.
  
  
  METHODS
  In June 2012, we conducted a nation-wide web-based survey to identify the prevalence and characteristics of allergic diseases among Japanese children. The prevalence of allergic diseases including eczema was assessed using the International Study of Asthma and Allergies in Childhood core questionnaire. The associations between eczema prevalence and environmental factors, as well as those between background characteristics and comorbid allergic diseases among 6-12 year old children were assessed.
  
  
  RESULTS
  A total of 28,348 children were included in the analysis. The prevalence of current eczema was 13.0%. Current eczema was significantly associated with a higher prevalence of wheeze, rhinitis, and food allergy. In multiple logistic regression models, birth during autumn (aOR: 1.18 95%CI: 1.06-1.31) or winter (aOR: 1.21 95%CI: 1.08-1.34), duration of exclusive breastfeeding for at least 6 months (aOR: 1.14 95%CI: 1.06-1.23), and ownership of a pet from infancy (aOR: 2.61 95%CI: 1.68-4.07) were also associated with a higher prevalence of eczema. The prevalence was lower in those with a high annual household income (aOR: 0.90 95%CI: 0.81-0.99) and 2 or more siblings (aOR: 0.86 95%CI: 0.76-0.97).
  
  
  CONCLUSIONS
  Duration of breastfeeding, season of birth, pet ownership, household income, and the number of siblings were associated with the prevalence of childhood eczema in a nationwide web survey.
authors.affiliation: Division of Allergy, Tokyo Metropolitan Children's Medical Center, Tokyo, Japan. Electronic address: mari_sasaki@tmhp.jp.
authors.forename: Mari
authors.initials: M
authors.lastname: Sasaki
authors.affiliation: Division of Allergy, Tokyo Metropolitan Children's Medical Center, Tokyo, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Yoshida
authors.affiliation: Department of Pediatrics, University of Toyama, Toyama, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Adachi
authors.affiliation: Division of Allergy, Tokyo Metropolitan Children's Medical Center, Tokyo, Japan.
authors.forename: Mayumi
authors.initials: M
authors.lastname: Furukawa
authors.affiliation: Department of Pediatrics, University of Toyama, Toyama, Japan.
authors.forename: Toshiko
authors.initials: T
authors.lastname: Itazawa
authors.affiliation: Department of Pediatrics, Fukuoka National Hospital, Fukuoka, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Odajima
authors.affiliation: Department of Allergy and Immunology, National Research Institute for Child Health and Development, Tokyo, Japan.
authors.forename: Hirohisa
authors.initials: H
authors.lastname: Saito
authors.affiliation: Department of Dermatology, Integrated Health Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Michihiro
authors.initials: M
authors.lastname: Hide
authors.affiliation: Division of Allergy, Tokyo Metropolitan Children's Medical Center, Tokyo, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Akasawa
mesh_terms: D000367:Age Factors; D002648:Child; D015897:Comorbidity; D004485:Eczema / Q000453:epidemiology* / Q000209:etiology*; D004777:Environment; D005260:Female; D006801:Humans; D020407:Internet; D008297:Male; D016017:Odds Ratio; D015995:Prevalence; D062486:Public Health Surveillance; D012307:Risk Factors; D011795:Surveys and Questionnaires
keywords: Eczema; Epidemiology; Prevalence; Risk factor; Web survey