title: No association of vitamin D intake or 25-hydroxyvitamin D levels in childhood with risk of islet autoimmunity and type 1 diabetes: the Diabetes Autoimmunity Study in the Young (DAISY).
abstract: OBJECTIVE
  The aim of the study was to investigate the association between vitamin D intake and status and the risk of islet autoimmunity (IA) and subsequent type 1 diabetes in children at increased risk of type 1 diabetes.
  
  
  METHODS
  The Diabetes Autoimmunity Study in the Young (DAISY) in Denver, CO, USA, has been following children at increased risk of diabetes since 1993. As of February 2011, 198 children developed IA during follow-up of 2,644 DAISY children. Vitamin D intake and plasma 25-hydroxyvitamin D [25(OH)D] were measured longitudinally. Proportional hazards regression analyses of time to IA, or type 1 diabetes in IA-positive children, were conducted, with vitamin D intake and 25(OH)D as time-varying covariates. HRs were calculated for a standard deviation difference in exposure, with adjustment for confounders.
  
  
  RESULTS
  Intake of vitamin D was not associated with the risk of IA (adjusted HR 1.13; 95% CI 0.95, 1.35; p = 0.18) nor progression to diabetes in IA-positive children (adjusted HR 1.30; 95% CI 0.91, 1.86; p = 0.15). Moreover, 25(OH)D level was not associated with the risk of IA (adjusted HR 1.12; 95% CI 0.88, 1.43; p = 0.36), nor progression to diabetes in IA-positive children (adjusted HR 0.91; 95% CI 0.68, 1.22; p = 0.54). In the 128 children in whom we measured 25(OH)D at 9 months of age, 25(OH)D was not associated with risk of IA (n = 30 IA-positive children) (adjusted HR 1.02; 95% CI 0.96, 1.07; p = 0.58).
  
  
  CONCLUSIONS
  Neither vitamin D intake nor 25(OH)D levels throughout childhood were associated with the risk of IA or progression to type 1 diabetes in our population.
authors.affiliation: Department of Epidemiology, Colorado School of Public Health, University of Colorado, 13001 East 17th Place, Campus Box B119, Aurora, CO 80045, USA.
authors.forename: M
authors.initials: M
authors.lastname: Simpson
authors.forename: H
authors.initials: H
authors.lastname: Brady
authors.forename: X
authors.initials: X
authors.lastname: Yin
authors.forename: J
authors.initials: J
authors.lastname: Seifert
authors.forename: K
authors.initials: K
authors.lastname: Barriga
authors.forename: M
authors.initials: M
authors.lastname: Hoffman
authors.forename: T
authors.initials: T
authors.lastname: Bugawan
authors.forename: A E
authors.initials: AE
authors.lastname: Barón
authors.forename: R J
authors.initials: RJ
authors.lastname: Sokol
authors.forename: G
authors.initials: G
authors.lastname: Eisenbarth
authors.forename: H
authors.initials: H
authors.lastname: Erlich
authors.forename: M
authors.initials: M
authors.lastname: Rewers
authors.forename: J M
authors.initials: JM
authors.lastname: Norris
mesh_terms: D015652:25-Hydroxyvitamin D 2 / Q000097:blood; D015551:Autoimmunity; D002112:Calcifediol / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003120:Colorado / Q000453:epidemiology; D003922:Diabetes Mellitus, Type 1 / Q000209:etiology* / Q000276:immunology*; D004032:Diet / Q000009:adverse effects; D019587:Dietary Supplements / Q000009:adverse effects; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007515:Islets of Langerhans / Q000276:immunology*; D008137:Longitudinal Studies; D008297:Male; D011446:Prospective Studies; D012306:Risk; D011795:Surveys and Questionnaires; D014807:Vitamin D / Q000008:administration & dosage* / Q000009:adverse effects; D014808:Vitamin D Deficiency / Q000503:physiopathology*
chemical_list: D014807:Vitamin D; D015652:25-Hydroxyvitamin D 2; D002112:Calcifediol