title: No effect of high-dose vitamin D supplementation on glycemic status or cardiovascular risk factors in subjects with prediabetes.
abstract: OBJECTIVE
  In observational studies, low serum 25-hydroxyvitamin D [25(OH)D] concentrations have been associated with insulin resistance and other risk factors for cardiovascular disease.
  
  
  METHODS
  We present 1-year data from an ongoing 5-year trial in 511 individuals with impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT) randomly assigned to 20,000 IU/week vitamin D3 or placebo. An oral glucose tolerance test was performed at baseline and after 1 year.
  
  
  RESULTS
  Mean baseline serum 25(OH)D was 59.9 nmol/L and 61.1 nmol/L in the vitamin D and placebo groups, respectively, and increased by 45.8 nmol/L and 3.4 nmol/L, respectively. With adjustment for baseline concentrations, no differences in measures of glucose metabolism, insulin secretion or sensitivity, blood pressure, or hs-CRP were found after 1 year. There was a slight, but significant decrease in total and LDL cholesterol in the vitamin D group compared with the placebo group, but as there was also a decrease in HDL cholesterol, the change in the total/HDL cholesterol ratio did not differ significantly. Only analyzing subjects with 25(OH)D <50 nmol/L did not change the results.
  
  
  CONCLUSIONS
  This study shows that vitamin D supplementation does not improve glycemic indices, blood pressure, or lipid status in subjects with IFG and/or IGT.
authors.affiliation: Tromsø Endocrine Research Group, The University of Tromsø - The Arctic University of Norway, Tromsø, NorwayDivision of Internal Medicine, University Hospital of North Norway, Tromsø, Norway stina.therese.sollid@unn.no.
authors.forename: Stina Therese
authors.initials: ST
authors.lastname: Sollid
authors.affiliation: Tromsø Endocrine Research Group, The University of Tromsø - The Arctic University of Norway, Tromsø, NorwayDivision of Rehabilitation Services, University Hospital of North Norway, Tromsø, Norway.
authors.forename: Moira Y S
authors.initials: MY
authors.lastname: Hutchinson
authors.affiliation: Division of Diagnostic Services, University Hospital of North Norway, Tromsø, Norway.
authors.forename: Ole M
authors.initials: OM
authors.lastname: Fuskevåg
authors.affiliation: Division of Diagnostic Services, University Hospital of North Norway, Tromsø, NorwayDepartment of Medical Biology, The University of Tromsø - The Arctic University of Norway, Tromsø, Norway.
authors.forename: Yngve
authors.initials: Y
authors.lastname: Figenschau
authors.affiliation: Tromsø Endocrine Research Group, The University of Tromsø - The Arctic University of Norway, Tromsø, NorwayDivision of Internal Medicine, University Hospital of North Norway, Tromsø, NorwayDepartment of Clinical Medicine, The University of Tromsø - The Arctic University of Norway, Tromsø, Norway.
authors.forename: Ragnar M
authors.initials: RM
authors.lastname: Joakimsen
authors.affiliation: Department of Clinical Medicine, The University of Tromsø - The Arctic University of Norway, Tromsø, Norway.
authors.forename: Henrik
authors.initials: H
authors.lastname: Schirmer
authors.affiliation: Department of Community Medicine, The University of Tromsø - The Arctic University of Norway, Tromsø, Norway.
authors.forename: Inger
authors.initials: I
authors.lastname: Njølstad
authors.affiliation: Tromsø Endocrine Research Group, The University of Tromsø - The Arctic University of Norway, Tromsø, NorwayDivision of Internal Medicine, University Hospital of North Norway, Tromsø, NorwayDepartment of Clinical Medicine, The University of Tromsø - The Arctic University of Norway, Tromsø, Norway.
authors.forename: Johan
authors.initials: J
authors.lastname: Svartberg
authors.affiliation: Tromsø Endocrine Research Group, The University of Tromsø - The Arctic University of Norway, Tromsø, NorwayDivision of Internal Medicine, University Hospital of North Norway, Tromsø, Norway.
authors.forename: Elena
authors.initials: E
authors.lastname: Kamycheva
authors.affiliation: Tromsø Endocrine Research Group, The University of Tromsø - The Arctic University of Norway, Tromsø, NorwayDivision of Internal Medicine, University Hospital of North Norway, Tromsø, NorwayDepartment of Clinical Medicine, The University of Tromsø - The Arctic University of Norway, Tromsø, Norway.
authors.forename: Rolf
authors.initials: R
authors.lastname: Jorde
mesh_terms: D015652:25-Hydroxyvitamin D 2 / Q000378:metabolism; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure / Q000502:physiology; D002112:Calcifediol / Q000378:metabolism; D002762:Cholecalciferol / Q000008:administration & dosage*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000517:prevention & control*; D003925:Diabetic Angiopathies / Q000517:prevention & control*; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D018149:Glucose Intolerance / Q000517:prevention & control; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000378:metabolism; D007333:Insulin Resistance / Q000502:physiology; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D011236:Prediabetic State / Q000097:blood / Q000517:prevention & control*; D012307:Risk Factors; D014807:Vitamin D / Q000031:analogs & derivatives / Q000378:metabolism; D014808:Vitamin D Deficiency / Q000097:blood / Q000178:diet therapy; D014815:Vitamins / Q000008:administration & dosage*; D055815:Young Adult
chemical_list: D007328:Insulin; D008055:Lipids; D014815:Vitamins; D014807:Vitamin D; D002762:Cholecalciferol; D015652:25-Hydroxyvitamin D 2; C104450:25-hydroxyvitamin D; D002112:Calcifediol