title: A multinational study to compare prevalence of atopic dermatitis in the first year of life.
abstract: BACKGROUND
  Atopic dermatitis (AD) is common in childhood, with peak prevalence in early childhood. However, international comparisons of prevalence have focused on older children. We analysed differences in prevalence rates of AD and the associations with putative risk and protective factors, among infants in two European and two Central American countries.
  
  
  METHODS
  In 1-yr old infants participating in the International Study of Wheezing in Infants (EISL), prevalence of AD and putative risk and protective factors were assessed by a questionnaire applied to parents. For each risk/protective factor summary, odds ratios with 95% confidence intervals were calculated by means of random effects meta-analysis.
  
  
  RESULTS
  Data from 9803 infants were analysed. AD prevalence varied from 10.6% (Valencia, Spain) to 28.2% (San Pedro Sula, Honduras). Average AD prevalences were lower in Europe (14.2%) than in Central America (18.2%, p < 0.01). Consistent with older children, presence of siblings decreased (OR 0.82 [0.72-0.94]), whereas family history of asthma (OR 1.32 [1.10-1.59]), rhinitis (OR 1.33 [1.14-1.54]) and atopic dermatitis (OR 2.40 [1.89-3.05]) increased the risk of infantile AD. However, gender, family size, breastfeeding and socio-economic status were not associated with AD prevalence.
  
  
  CONCLUSIONS
  This study shows almost threefold differences in the prevalence of AD in infancy between countries. Risk and protective factors involved in the expression of infantile AD differ from those in older children, possibly suggesting a different pathophysiology. There is a need for additional international epidemiological surveys on AD in young children, the peak prevalence age of this condition.
authors.affiliation: Princess Amalia Children's Centre, Isala Hospital, Zwolle, the Netherlands.
authors.forename: Eelco
authors.initials: E
authors.lastname: Draaisma
authors.affiliation: Pediatric Respiratory and Allergy Units, 'Virgen de la Arrixaca' University Children's Hospital, University of Murcia, Murcia, Spain.|Arrixaca Bio-Health Research Institute of Murcia, Murcia, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Garcia-Marcos
authors.affiliation: Department of Pediatric Respiratory Medicine, Hospital El Pino, University of Santiago de Chile (USACH), Santiago, Chile.
authors.forename: Javier
authors.initials: J
authors.lastname: Mallol
authors.affiliation: Division of Allergy, Clinical Immunology and Rheumatology, Department of Pediatrics, Federal University of São Paulo (UNIFESP), São Paulo, Brazil.
authors.forename: Dirceu
authors.initials: D
authors.lastname: Solé
authors.affiliation: Pediatric Respiratory and Allergy Units, 'Virgen de la Arrixaca' University Children's Hospital, University of Murcia, Murcia, Spain.
authors.forename: Virginia
authors.initials: V
authors.lastname: Pérez-Fernández
authors.affiliation: Princess Amalia Children's Centre, Isala Hospital, Zwolle, the Netherlands.|UMCG Postgraduate School of Medicine, University Medical Centre and University of Groningen, Groningen, the Netherlands.
authors.forename: Paul L P
authors.initials: PL
authors.lastname: Brand
mesh_terms: D003430:Cross-Sectional Studies; D003876:Dermatitis, Atopic / Q000453:epidemiology*; D005260:Female; D006721:Honduras / Q000453:epidemiology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D015995:Prevalence; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology; D011795:Surveys and Questionnaires
keywords: atopic dermatitis; infants; international; prevalence; protective factors; risk factors