Vitamin D AND Glucose Handling Evaluated by Glucose Clamp (D-clamp)

Vitamin D AND Cardiovascular Disease

In this study the investigators want to compare glucose handling (insulin secretion and insulin sensitivity) in 100 persons with low and 50 persons with normal-high levels of vitamin D, using a hyperglycemic clamp technique, were sugar is given intravenously for 3 hours in order to keep the blood sugar level at 10 mmol/L. Those with low vitamin D levels will be randomized to treatment with vitamin D3 (cholecalciferol) 40 000 IU/week or placebo for 6 months before a new clamp is performed.

The study hypothesis is that persons with low vitamin D levels have impaired glucose handling which might be improved by vitamin D supplementation.

Study Overview

• Status: Completed
• Conditions: Intraocular Pressure; Insulin Sensitivity
• Intervention / Treatment: Drug: cholecalciferol

• Study Type: Interventional
• Enrollment (Actual): 160
• Phase: Phase 2

Contacts and Locations

Study Locations

• Norway
  • Tromsø, Norway, 9037
    • University Hospital of North Norway

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 30 years to 75 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• generally: Subjects are recruited from the 6th Tromsø Study
• cases: serum 25-hydroxyvitamin D-levels below the 10 percentile; low levels confirmed with new serum analyses.
• controls: serum 25-hydroxyvitamin D levels 80-95 percentile, normal-high levels confirmed with new serum analyses.

Exclusion Criteria:

• diabetes
• myocardial infarction or apoplexia
• active cancer during last 5 years
• history of kidney stone
• pregnancy or premenopausal without safe anticonception
• primary hyperparathyroidism
• systolic blood pressure >175 or diastolic blood pressure >105

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
intraocular pressure	6 months
insulin secretion and sensitivity as assessed by an hyperglycemic clamp	6 months

Secondary Outcome Measures

Outcome Measure	Time Frame
telomer length	6 months
25-hydroxyvitamin D and 1,25-dihydroxyvitamin D-levels	6 months
serum calcium, PTH, phosphate	6 months
inflammatory markers and lipids	6 months

Collaborators and Investigators

• Sponsor: University Hospital of North Norway
• Collaborators: Norwegian Council on Cardiovascular diseases
• Investigators: Principal Investigator: Rolf Jorde, Professor, Medical Dpt, University Hospital of Northern Norway

Publications and helpful links

General Publications

• Grimnes G, Figenschau Y, Almas B, Jorde R. Vitamin D, insulin secretion, sensitivity, and lipids: results from a case-control study and a randomized controlled trial using hyperglycemic clamp technique. Diabetes. 2011 Nov;60(11):2748-57. doi: 10.2337/db11-0650. Epub 2011 Sep 12.

Study record dates

Study Major Dates

• Study Start: November 1, 2008
• Primary Completion (Actual): December 1, 2010
• Study Completion (Actual): December 1, 2010

Study Registration Dates

• First Submitted: December 16, 2008
• First Submitted That Met QC Criteria: December 16, 2008
• First Posted (Estimate): December 17, 2008

Study Record Updates

• Last Update Posted (Estimate): November 3, 2011
• Last Update Submitted That Met QC Criteria: November 2, 2011
• Last Verified: November 1, 2011

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Glucose Metabolism Disorders; Metabolic Diseases; Hyperinsulinism; Insulin Resistance; Physiological Effects of Drugs; Micronutrients; Vitamins; Bone Density Conservation Agents; Calcium-Regulating Hormones and Agents; Vitamin D; Cholecalciferol
• Other Study ID Numbers: UIT-ENDO-2008-GURI-2