title: A randomised controlled trial of high dose vitamin D in recent-onset type 2 diabetes.
abstract: OBJECTIVE
  Vitamin D insufficiency has been associated with impaired pancreatic beta-cell function. We aimed to determine if high dose oral vitamin D3 (D) improves beta-cell function and glycaemia in type 2 diabetes.
  
  
  METHODS
  Fifty adults with type 2 diabetes diagnosed less than 12 months, with normal baseline serum 25-OH D (25D), were randomised to 6000 IU D (n=26) or placebo (n=24) daily for 6 months. Beta-cell function was measured by glucagon-stimulated serum C-peptide (delta C-peptide [DCP], nmol/l). Secondary outcome measures were fasting plasma glucose (FPG), post-prandial blood glucose (PPG), HbA1c and insulin resistance (HOMA-IR).
  
  
  RESULTS
  In the D group, median serum 25D (nmol/l) increased from 59 to 150 (3 months) and 128 (6 months) and median serum 1,25D (pmol/l) from 135 to 200 and 190. After 3 months, change in DCP from baseline in D (+0.04) and placebo (-0.08) was not different (P=0.112). However, change in FPG (mmol/l) was significantly lower in D (-0.40) compared to placebo (+0.1) (P=0.007), as was the change in PPG in D (-0.30) compared to placebo (+0.8) (P=0.005). Change in HbA1c (%) between D (-0.20) and placebo (-0.10) was not different (P=0.459). At 6 months, changes from baseline in DCP, FPG, PPG and HbA1c were not different between groups.
  
  
  CONCLUSIONS
  Oral D3 supplementation in type 2 diabetes was associated with transient improvement in glycaemia, but without a measurable change in beta-cell function this effect is unlikely to be biologically significant. High dose D3 therefore appears to offer little or no therapeutic benefit in type 2 diabetes.
authors.affiliation: Walter & Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville 3052, VIC, Australia; Burnet Clinical Research Unit, Royal Melbourne Hospital, Parkville 3050, VIC, Australia.
authors.forename: Shirley
authors.initials: S
authors.lastname: Elkassaby
authors.affiliation: Walter & Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville 3052, VIC, Australia; Burnet Clinical Research Unit, Royal Melbourne Hospital, Parkville 3050, VIC, Australia. Electronic address: harrison@wehi.edu.au.
authors.forename: Leonard C
authors.initials: LC
authors.lastname: Harrison
authors.affiliation: Walter & Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville 3052, VIC, Australia; Burnet Clinical Research Unit, Royal Melbourne Hospital, Parkville 3050, VIC, Australia.
authors.forename: Namita
authors.initials: N
authors.lastname: Mazzitelli
authors.affiliation: Walter & Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville 3052, VIC, Australia; Department of Diabetes & Endocrinology, Royal Melbourne Hospital, Parkville 3050, VIC, Australia.
authors.forename: John M
authors.initials: JM
authors.lastname: Wentworth
authors.affiliation: Department of Diabetes & Endocrinology, Royal Melbourne Hospital, Parkville 3050, VIC, Australia.
authors.forename: Peter G
authors.initials: PG
authors.lastname: Colman
authors.affiliation: Burnet Institute, 85 Commercial Road, Melbourne 3004, VIC, Australia.
authors.forename: Timothy
authors.initials: T
authors.lastname: Spelman
authors.affiliation: Burnet Clinical Research Unit, Royal Melbourne Hospital, Parkville 3050, VIC, Australia.
authors.forename: Spiros
authors.initials: S
authors.lastname: Fourlanos
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D002096:C-Peptide / Q000097:blood; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000150:complications* / Q000188:drug therapy; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use; D007328:Insulin / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D013997:Time Factors; D014807:Vitamin D / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D014808:Vitamin D Deficiency / Q000097:blood / Q000188:drug therapy* / Q000209:etiology
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D002096:C-Peptide; D007004:Hypoglycemic Agents; D007328:Insulin; D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: ACTRN 12611001023943; Beta-cell function; Glycaemia; Randomised trial; Type 2 diabetes; Vitamin D