title: Impact of treatment with oral calcitriol on glucose indices in type 2 diabetes mellitus patients.
abstract: BACKGROUND
  Type 2 diabetes is a major public health problem. Recent epidemiological evidence also points to a potential association of vitamin D insufficiency with adverse metabolic risks, including that for type 2 diabetes.
  
  
  METHODS
  A double-blind randomized placebo-controlled trial was carried out. Seventy subjects with type 2 diabetes, age 30-75 years old, were randomly assigned in a double-blind fashion to two groups. One group received two capsules of calcitriol (0.25 μg 1,25-dihydroxy cholecalciferol per each capsule) per day. The second group received placebo tablets. At the beginning, middle and the end of the 12 week supplementation trial, serum glucose, insulin, calcium and phosphorous, HbA1c and 25(OH) vitamin D were measured.
  
  
  RESULTS
  There was no significant difference between two groups at baseline. At the end of the study, fasting plasma glucose increased in the control group (p=0.038), while it remained unchanged in calcitriol group. Level of insulin and HbA1c increased significantly in both groups (p=0.013 and 0.0004 in treatment and control group). Regarding insulin resistance indices, there was a significant change in HOMA-IR and QUICKI in both groups (p=0.023 and 0.002 in treatment and 0.001 and <0.001 in control group respectively). Insulin secretion as assessed by HOMA-%β, remained relatively unchanged in the control group, while it increased significantly in the treatment group at the end of study (p=0.009).
  
  
  CONCLUSIONS
  Vitamin D supplementation attenuated the increase in glycemia, and increased insulin secretion, but had no effect on insulin resistance.
authors.affiliation: Nutrition Department, Research Center for Health Sciences, School of Health and Nutrition, Shiraz University of Medical Sciences, Shiraz. I.R. Iran. h_eftekhari@yahoo.com
authors.forename: Mohammad Hassan
authors.initials: MH
authors.lastname: Eftekhari
authors.forename: Marzieh
authors.initials: M
authors.lastname: Akbarzadeh
authors.forename: Mohammad Hossein
authors.initials: MH
authors.lastname: Dabbaghmanesh
authors.forename: Jafar
authors.initials: J
authors.lastname: Hasanzadeh
mesh_terms: D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000187:drug effects*; D002117:Calcitriol / Q000008:administration & dosage* / Q000097:blood; D003924:Diabetes Mellitus, Type 2; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D006442:Glycated Hemoglobin / Q000187:drug effects; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome
chemical_list: D001786:Blood Glucose; D002117:Calcitriol; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human