title: Vitamin D levels and atopic eczema in infancy and early childhood in Norway: a cohort study.
abstract: BACKGROUND
  Epidemiological data and the effect of sun exposure on atopic eczema (AE) suggest that vitamin D (vitD) may be involved in the pathogenesis.
  
  
  OBJECTIVE
  To investigate if vitD levels were associated with the presence or severity of AE in the first 2 years of life in children living in south-east Norway.
  
  
  METHODS
  Infants, recruited to a clinical trial on acute bronchiolitis (n = 404) and from the general population (n = 240), were examined at 1-13 months (first visit) and at 2 years of age (second visit). Caregivers were interviewed using a structured questionnaire. AE was diagnosed clinically, based on well-established criteria. Disease severity was assessed using the SCORing Atopic Dermatitis index. Blood samples were taken for vitD measurements, using liquid chromatography-tandem mass spectrometry and for common filaggrin mutation analyses. Complete data on AE and vitD were available in 596 and 449 children at the first and second visit, respectively.
  
  
  RESULTS
  Atopic eczema was diagnosed in 67 children (11%) at the first visit and in 103 children (23%) at the second. Mean vitD levels were 58·2 nmol L(-1) at the first visit and 66·9 nmol L(-1) at the second. Using vitD level tertiles in multivariate regression analysis, there was no association between vitD levels and AE at either visit, regardless of filaggrin mutation. In children without AE at the first visit, vitD levels did not predict AE at the second.
  
  
  CONCLUSIONS
  In this cohort of young children in Norway, we found no association between vitD levels and the presence or severity of AE.
authors.affiliation: Institute of Clinical Medicine, University of Oslo, Oslo, Norway.|Department of Dermatology, Oslo University Hospital, Oslo, Norway.
authors.forename: T L
authors.initials: TL
authors.lastname: Berents
authors.affiliation: Institute of Clinical Medicine, University of Oslo, Oslo, Norway.|Department of Pediatrics, Oslo University Hospital, Oslo, Norway.
authors.forename: K C
authors.initials: KC
authors.lastname: Lødrup Carlsen
authors.affiliation: Department of Pediatrics, Oslo University Hospital, Oslo, Norway.
authors.forename: P
authors.initials: P
authors.lastname: Mowinckel
authors.affiliation: Institute of Clinical Medicine, University of Oslo, Oslo, Norway.|Department of Biostatistics and Epidemiology, Oslo University Hospital, Oslo, Norway.|University of Oslo, Oslo, Norway.
authors.forename: L
authors.initials: L
authors.lastname: Sandvik
authors.affiliation: Institute of Clinical Medicine, University of Oslo, Oslo, Norway.|Department of Pediatrics, Oslo University Hospital, Oslo, Norway.
authors.forename: H O
authors.initials: HO
authors.lastname: Skjerven
authors.affiliation: Institute of Clinical Medicine, University of Oslo, Oslo, Norway.|Department of Pediatrics, Elverum Hospital, Elverum, Norway.
authors.forename: L B
authors.initials: LB
authors.lastname: Rolfsjord
authors.affiliation: Department of Pediatrics, Østfold Hospital, Fredrikstad, Norway.
authors.forename: B
authors.initials: B
authors.lastname: Kvenshagen
authors.affiliation: Institute of Clinical Medicine, University of Oslo, Oslo, Norway.|Department of Pediatrics, Oslo University Hospital, Oslo, Norway.|Department of Pediatrics, Østfold Hospital, Fredrikstad, Norway.
authors.forename: J O G
authors.initials: JO
authors.lastname: Hunderi
authors.affiliation: Department of Molecular Medicine, Karolinska Institute at Karolinska Hospital, Stockholm, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Bradley
authors.affiliation: Department of Molecular Medicine, Karolinska Institute at Karolinska Hospital, Stockholm, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Lieden
authors.affiliation: Institute of Clinical Medicine, University of Oslo, Oslo, Norway.|Department of Pediatrics, Oslo University Hospital, Oslo, Norway.
authors.forename: K-H
authors.initials: KH
authors.lastname: Carlsen
authors.affiliation: Institute of Clinical Medicine, University of Oslo, Oslo, Norway.|Hormone Laboratory, Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway.
authors.forename: P M
authors.initials: PM
authors.lastname: Thorsby
authors.affiliation: Institute of Clinical Medicine, University of Oslo, Oslo, Norway.|Department of Dermatology, Oslo University Hospital, Oslo, Norway.
authors.forename: P
authors.initials: P
authors.lastname: Gjersvik
mesh_terms: D015652:25-Hydroxyvitamin D 2 / Q000378:metabolism*; D002112:Calcifediol / Q000378:metabolism*; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D003876:Dermatitis, Atopic / Q000097:blood / Q000453:epidemiology* / Q000235:genetics; D000091344:Filaggrin Proteins; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007381:Intermediate Filament Proteins / Q000235:genetics; D009154:Mutation / Q000235:genetics; D009664:Norway / Q000453:epidemiology; D011446:Prospective Studies; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology / Q000235:genetics
chemical_list: C000717249:FLG protein, human; D000091344:Filaggrin Proteins; D007381:Intermediate Filament Proteins; D015652:25-Hydroxyvitamin D 2; D002112:Calcifediol