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

This study has been completed.
Sponsor:
ClinicalTrials.gov Identifier:
NCT00809744
First Posted: December 17, 2008
Last Update Posted: November 3, 2011
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
Collaborator:
Norwegian Council on Cardiovascular diseases
Information provided by (Responsible Party):
University Hospital of North Norway
  Purpose

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.


Condition Intervention Phase
Insulin Sensitivity Intraocular Pressure Drug: cholecalciferol Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Basic Science
Official Title: Vitamin D AND Cardiovascular Disease

Resource links provided by NLM:


Further study details as provided by University Hospital of North Norway:

Primary Outcome Measures:
  • insulin secretion and sensitivity as assessed by an hyperglycemic clamp [ Time Frame: 6 months ]
  • intraocular pressure [ Time Frame: 6 months ]

Secondary Outcome Measures:
  • telomer length [ Time Frame: 6 months ]
  • 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D-levels [ Time Frame: 6 months ]
  • serum calcium, PTH, phosphate [ Time Frame: 6 months ]
  • inflammatory markers and lipids [ Time Frame: 6 months ]

Enrollment: 160
Study Start Date: November 2008
Study Completion Date: December 2010
Primary Completion Date: December 2010 (Final data collection date for primary outcome measure)
Intervention Details:
    Drug: cholecalciferol
    capsules, 20 000IU, twice a week, 6 months duration
  Eligibility

Information from the National Library of Medicine

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Ages Eligible for Study:   30 Years to 75 Years   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Criteria

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
  Contacts and Locations
Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00809744


Locations
Norway
University Hospital of North Norway
Tromsø, Norway, 9037
Sponsors and Collaborators
University Hospital of North Norway
Norwegian Council on Cardiovascular diseases
Investigators
Principal Investigator: Rolf Jorde, Professor Medical Dpt, University Hospital of Northern Norway
  More Information

Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: University Hospital of North Norway
ClinicalTrials.gov Identifier: NCT00809744     History of Changes
Other Study ID Numbers: UIT-ENDO-2008-GURI-2
First Submitted: December 16, 2008
First Posted: December 17, 2008
Last Update Posted: November 3, 2011
Last Verified: November 2011

Additional relevant MeSH terms:
Insulin Resistance
Hyperinsulinism
Glucose Metabolism Disorders
Metabolic Diseases
Vitamin D
Cholecalciferol
Vitamins
Micronutrients
Growth Substances
Physiological Effects of Drugs
Bone Density Conservation Agents