title: Atopic dermatitis and birth factors: historical follow up by record linkage.
abstract: OBJECTIVE
  To study if factors at birth are associated with later development of atopic dermatitis.
  
  
  METHODS
  Historical follow up by record linkage from Danish medical birth register. Children were followed up for 5.5 to 8.5 years. Second historical follow up study comprising questionnaire to mothers of singleborn children 6.5 to 9.5 years after birth.
  
  
  METHODS
  Private dermatology clinics and dermatology and paediatric departments in the municipality of Aarhus, Denmark.
  
  
  METHODS
  7862 singletons born in hospital between 1 January 1984 and 31 December 1986 to mothers living in the municipality of Aarhus. Questionnaires sent to 985 mothers.
  
  
  METHODS
  Gestational age, birth weight, parity, and age of mother at the time of birth. Atopy in children diagnosed by specialists in dermatology and physicians. Family size; diagnosis of atopic dermatitis, allergic rhinitis, and asthma; family predisposition; and mothers' smoking habits during pregnancy determined from questionnaires.
  
  
  RESULTS
  Of 7862 children, 403 were diagnosed as having atopic dermatitis by a specialist; the cumulative incidence at age 7 was 5.6%. High gestational age and low parity were associated with an increased risk of atopic dermatitis. Among 985 children atopic dermatitis had been diagnosed by any physician in 184; the cumulative incidence at age 7 was 18.7%. High birth weight, high gestational age, and family history of atopy were associated with increased risk of atopic dermatitis.
  
  
  CONCLUSIONS
  In both studies the incidence of atopic dermatitis was associated with high gestational age and in one with high birth weight also. The causes for these associations are at present unknown but may indicate that even during gestation factors associated with atopic dermatitis influence maturation.
authors.affiliation: Department of Dermatology, Aarhus University Hospital, Marselisborg, Denmark.
authors.forename: A B
authors.initials: AB
authors.lastname: Olesen
authors.forename: A R
authors.initials: AR
authors.lastname: Ellingsen
authors.forename: H
authors.initials: H
authors.lastname: Olesen
authors.forename: S
authors.initials: S
authors.lastname: Juul
authors.forename: K
authors.initials: K
authors.lastname: Thestrup-Pedersen
mesh_terms: D000328:Adult; D000367:Age Factors; D001724:Birth Weight; D002648:Child; D002675:Child, Preschool; D003718:Denmark / Q000453:epidemiology; D003876:Dermatitis, Atopic / Q000453:epidemiology / Q000209:etiology* / Q000235:genetics; D005260:Female; D005500:Follow-Up Studies; D005865:Gestational Age; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D008423:Maternal Age; D008498:Medical Record Linkage; D010298:Parity; D010375:Pedigree; D011247:Pregnancy; D012307:Risk Factors