title: Establishing the prevalence of low vitamin D in non-immunoglobulin-E mediated gastrointestinal food allergic children in a tertiary centre.
abstract: BACKGROUND
  There is no data on the prevalence of vitamin D deficiency in children with non-immunoglobulin-E (IgE) mediated gastrointestinal food allergy. The aims of our study were to understand the prevalence of vitamin D insufficiency and deficiency in children with non-IgE mediated gastrointestinal food allergy and identify predisposing factors.
  
  
  METHODS
  This was a retrospective study which looked at data from Great Ormond Street Hospital from January 2002 to September 2015. Children 0-18 years old with a confirmed diagnosis of non-IgE mediated gastrointestinal food allergy who had a vitamin D level measured during the course of their disease were included. Low vitamin D levels were defined as <50 nmol/L; insufficient levels were defined as 25-50 nmol/L and deficient levels as <25 nmol/L. Patient characteristics and clinical factors were also recorded.
  
  
  RESULTS
  Ninety-two patients met the study criteria; 49% were female and median age was 10 years 2 months [IQR: 4 years 8 months to 13 years 7 months]. Of the cohort, 26% (24/92) had low vitamin D levels; 16% had insufficient vitamin D levels and 10% had vitamin D deficiency. Gender (p= 0.043) and age (p= 0.035) were significantly associated with low vitamin D levels. Twelve percent of children who were on an amino acid formula (AAF) had low vitamin D compared to 31% of children who were not (p= 0.06). No other clinical factors were found to be significantly associated with low vitamin D levels.
  
  
  CONCLUSIONS
  Children with non-IgE mediated gastrointestinal food allergy are at risk of vitamin D insufficiency and deficiency. Further prospective studies need to be performed in all children with non-IgE mediated gastrointestinal food allergies.
  
  
  BACKGROUND
  The study was registered with the GOSH Research & Development department as a retrospective case note review. The Health Research Authority confirmed that NHS Research and Ethics Committee approval was not required; thus there is no trial registration number.
authors.affiliation: Paediatric Gastroenterology Department, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK ; Institute of Child Health, University College, London, UK.
authors.forename: Ru-Xin
authors.initials: RX
authors.lastname: Foong
authors.affiliation: Imperial College of London, London, UK.
authors.forename: Rosan
authors.initials: R
authors.lastname: Meyer
authors.affiliation: Paediatric Gastroenterology Department, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK.
authors.forename: Robert
authors.initials: R
authors.lastname: Dziubak
authors.affiliation: Paediatric Gastroenterology Department, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK.
authors.forename: Adriana Chebar
authors.initials: AC
authors.lastname: Lozinsky
authors.affiliation: Paediatric Gastroenterology Department, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK.
authors.forename: Heather
authors.initials: H
authors.lastname: Godwin
authors.affiliation: Paediatric Gastroenterology Department, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK.
authors.forename: Kate
authors.initials: K
authors.lastname: Reeve
authors.affiliation: Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
authors.forename: Syeda Tahmida
authors.initials: ST
authors.lastname: Hussain
authors.affiliation: Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
authors.forename: Romman
authors.initials: R
authors.lastname: Nourzaie
authors.affiliation: Paediatric Gastroenterology Department, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK ; Institute of Child Health, University College, London, UK.
authors.forename: Neil
authors.initials: N
authors.lastname: Shah
keywords: Non-IgE mediated allergy; Paediatrics; Vitamin D