title: Serum vitamin D concentration does not predict insulin action or secretion in European subjects with the metabolic syndrome.
abstract: OBJECTIVE
  To investigate the relation between serum concentration of 25-hydroxyvitamin D [25(OH)D] and insulin action and secretion.
  
  
  METHODS
  In a cross-sectional study of 446 Pan-European subjects with the metabolic syndrome, insulin action and secretion were assessed by homeostasis model assessment (HOMA) indexes and intravenous glucose tolerance test to calculate acute insulin response, insulin sensitivity, and disposition index. Serum 25(OH)D was measured by high-performance liquid chromatography/mass spectrometry.
  
  
  RESULTS
  The 25(OH)D(3) concentration was 57.1 +/- 26.0 nmol/l (mean +/- SD), and only 20% of the subjects had 25(OH)D(3) levels > or =75 nmol/l. In multiple linear analyses, 25(OH)D(3) concentrations were not associated with parameters of insulin action or secretion after adjustment for BMI and other covariates.
  
  
  CONCLUSIONS
  In a large sample of subjects with the metabolic syndrome, serum concentrations of 25(OH)D(3) did not predict insulin action or secretion. Clear evidence that D vitamin status directly influences insulin secretion or action is still lacking.
authors.affiliation: Department of Clinical Endocrinology, Oslo University Hospital Aker, University of Oslo, Oslo, Norway. h.l.gulseth@medisin.uio.no
authors.forename: Hanne L
authors.initials: HL
authors.lastname: Gulseth
authors.forename: Ingrid M F
authors.initials: IM
authors.lastname: Gjelstad
authors.forename: Audrey C
authors.initials: AC
authors.lastname: Tierney
authors.forename: Julie A
authors.initials: JA
authors.lastname: Lovegrove
authors.forename: Catherine
authors.initials: C
authors.lastname: Defoort
authors.forename: Ellen E
authors.initials: EE
authors.lastname: Blaak
authors.forename: Jose
authors.initials: J
authors.lastname: Lopez-Miranda
authors.forename: Beata
authors.initials: B
authors.lastname: Kiec-Wilk
authors.forename: Ulf
authors.initials: U
authors.lastname: Risérus
authors.forename: Ulférus
authors.initials: U
authors.lastname: Ris
authors.forename: Helen M
authors.initials: HM
authors.lastname: Roche
authors.forename: Christian A
authors.initials: CA
authors.lastname: Drevon
authors.forename: Kåre I
authors.initials: KI
authors.lastname: Birkeland
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood*; D008875:Middle Aged; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D