title: Incidence rates of atopic dermatitis, asthma, and allergic rhinoconjunctivitis in Danish and Swedish children.
abstract: BACKGROUND
  Several studies have shown that the prevalence of the frequent chronic conditions of atopic dermatitis, asthma, and allergy has increased substantially for reasons not fully understood. Atopic diseases affect quality of life in both children and their family members.
  
  
  OBJECTIVE
  Using national registers, we sought to establish up-to-date incidence rates of atopic dermatitis, asthma, and allergic rhinoconjunctivitis in the Danish and Swedish child populations.
  
  
  METHODS
  Children born in Denmark from 1997 to 2011 or born in Sweden from 2006 to 2010 participated in this cross-national, population-based cohort study. Incidence rates of atopic dermatitis, asthma, and allergic rhinoconjunctivitis in the Danish and Swedish child cohorts were ascertained through disease-specific dispensed prescribed medication, specific hospital contacts, or both.
  
  
  RESULTS
  In both countries the incidence rate of atopic dermatitis was stable during the study periods. The incidence rate of asthma increased until 2006 and stabilized for the rest of the study period in Denmark and increased in Sweden. The incidence rate of allergic rhinoconjunctivitis decreased in both countries.
  
  
  CONCLUSIONS
  The study revealed similar trends, with stable incidence rates of atopic dermatitis in both Danish and Swedish children, an increase and then stabilization in asthma incidence rates in Denmark and an increase in Sweden, and a decrease in allergic rhinoconjunctivitis incidence rates. At age 5 years, one third of all children were affected with at least one of the conditions of atopic dermatitis, asthma, or allergic rhinoconjunctivitis.
authors.affiliation: Research Unit Women's and Children's Health 7821, Child and Adolescent Clinic 4072, and Danish National University Hospital Rigshospitalet, Copenhagen, Denmark. Electronic address: lonnyhenriksen@gmail.com.
authors.forename: Lonny
authors.initials: L
authors.lastname: Henriksen
authors.affiliation: Department of Epidemiology Research, Statens Serum Institute, Copenhagen, Denmark.
authors.forename: Jacob
authors.initials: J
authors.lastname: Simonsen
authors.affiliation: Research Unit Women's and Children's Health 7821, Child and Adolescent Clinic 4072, and Danish National University Hospital Rigshospitalet, Copenhagen, Denmark.
authors.forename: Ann
authors.initials: A
authors.lastname: Haerskjold
authors.affiliation: Centre of Pharmacoepidemiology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Marie
authors.initials: M
authors.lastname: Linder
authors.affiliation: Centre of Pharmacoepidemiology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Helle
authors.initials: H
authors.lastname: Kieler
authors.affiliation: Department of Dermatology, Bispebjerg Hospital, Copenhagen, Denmark.
authors.forename: Simon Francis
authors.initials: SF
authors.lastname: Thomsen
authors.affiliation: Child and Adolescent Clinic 4072, the Danish National University Hospital Rigshospitalet, Copenhagen, Denmark.
authors.forename: Lone Graff
authors.initials: LG
authors.lastname: Stensballe
mesh_terms: D000293:Adolescent; D001249:Asthma / Q000453:epidemiology* / Q000276:immunology / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D002908:Chronic Disease; D003233:Conjunctivitis, Allergic / Q000453:epidemiology* / Q000276:immunology / Q000473:pathology; D003430:Cross-Sectional Studies; D003718:Denmark; D003876:Dermatitis, Atopic / Q000453:epidemiology* / Q000276:immunology / Q000473:pathology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D012042:Registries; D006255:Rhinitis, Allergic, Seasonal / Q000453:epidemiology* / Q000276:immunology / Q000473:pathology; D013548:Sweden
keywords: Atopy; children; incidence rate; pharmacoepidemiology