title: 25-Hydroxyvitamin D concentrations, asthma and eczema in childhood: The generation R study.
abstract: A role of vitamin D in the development of respiratory and allergic disease in children remains unclear. It may be likely that vitamin D has an effect on airway inflammation, but only few studies examined the effect in children. We aimed to examine whether serum 25-hydroxyvitamin D (25(OH) vitamin D) concentrations are associated with the fraction of exhaled nitric oxide (FeNO), airway interrupter resistance (Rint), physician diagnosed asthma ever, wheezing and eczema in a population-based cohort study in 6 year old children.
  
  
  
  Serum 25(OH) vitamin D concentration was assessed in 3815 children. 25(OH) vitamin D concentrations ≥75 nmol/L were considered as sufficient, between 50 and 75 nmol/L as insufficient, and <50 nmol/L as deficient. FeNO and Rint were measured at the research center. Data on physician diagnosed asthma, wheezing, and eczema were obtained by parent-reported questionnaires.
  
  
  
  In comparison with sufficient 25(OH) vitamin D concentration, deficient concentrations were associated with elevated FeNO of ≥25 ppb (OR: 2.54; 95% CI: 1.34-4.80). In addition, deficient and insufficient 25(OH) vitamin D concentrations were associated with a lower Rint (Z-score: -1.26; 95% CI: -1.66 to -0.85) (ß: -0.75; 95% CI: -1.08 to -0.42), and increased risks of eczema (OR: 1.65; 95% CI: 1.13-2.41) (OR: 1.44; 95% CI: 1.06-1.95). Insufficient 25(OH) vitamin D concentration were associated with a decreased risk of physician diagnosed asthma ever (OR: 0.59; 95% CI: 0.38-0.94).
  
  
  
  Our results indicate that lower 25(OH) vitamin D levels are associated with elevated FeNO levels, but lower Rint values. Lower 25(OH) vitamin D levels are also associated with a decreased risk for asthma diagnoses but an increased risk for eczema.
authors.affiliation: From the Generation R Study Group, The Netherlands; Departments of Pediatrics, Erasmus University, Rotterdam, The Netherlands.
authors.forename: Ilse I M
authors.initials: IIM
authors.lastname: Tromp
authors.affiliation: Departments of Epidemiology, Erasmus University, Rotterdam, The Netherlands.
authors.forename: Oscar H
authors.initials: OH
authors.lastname: Franco
authors.affiliation: Departments of Epidemiology, Erasmus University, Rotterdam, The Netherlands.
authors.forename: Edith H
authors.initials: EH
authors.lastname: van den Hooven
authors.affiliation: Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Annemieke C
authors.initials: AC
authors.lastname: Heijboer
authors.affiliation: From the Generation R Study Group, The Netherlands; Departments of Epidemiology, Erasmus University, Rotterdam, The Netherlands; Departments of Pediatrics, Erasmus University, Rotterdam, The Netherlands.
authors.forename: Vincent W V
authors.initials: VWV
authors.lastname: Jaddoe
authors.affiliation: Departments of Epidemiology, Erasmus University, Rotterdam, The Netherlands; Division of Respiratory Medicine, Erasmus University, Rotterdam, The Netherlands; Division of Neonatology, Erasmus University, Rotterdam, The Netherlands.
authors.forename: Liesbeth
authors.initials: L
authors.lastname: Duijts
authors.affiliation: Division of Respiratory Medicine, Erasmus University, Rotterdam, The Netherlands.
authors.forename: Johan C
authors.initials: JC
authors.lastname: de Jongste
authors.affiliation: Departments of Pediatrics, Erasmus University, Rotterdam, The Netherlands.
authors.forename: Henriëtte A
authors.initials: HA
authors.lastname: Moll
authors.affiliation: Departments of Epidemiology, Erasmus University, Rotterdam, The Netherlands; Global Public Health, Leiden University College, The Hague, The Netherlands; Departments of Pediatrics, Erasmus University, Rotterdam, The Netherlands. Electronic address: j.c.kiefte-dejong@erasmusmc.nl.
authors.forename: Jessica C
authors.initials: JC
authors.lastname: Kiefte-de Jong
mesh_terms: D001249:Asthma / Q000097:blood* / Q000453:epidemiology*; D002648:Child; D004485:Eczema / Q000097:blood* / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D009426:Netherlands / Q000453:epidemiology; D011446:Prospective Studies; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: 25-Hydroxyvitamin D; Asthma; Eczema; FeNO; Vitamin D; Wheezing