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

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ClinicalTrials.gov Identifier: NCT00809744
Recruitment Status : Completed
First Posted : December 17, 2008
Last Update Posted : November 3, 2011
Information provided by (Responsible Party):

Study Description
Brief Summary:

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 or disease Intervention/treatment Phase
Insulin Sensitivity Intraocular Pressure Drug: cholecalciferol Phase 2

Study Design

Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 160 participants
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
Study Start Date : November 2008
Primary Completion Date : December 2010
Study Completion Date : December 2010

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Vitamin D
U.S. FDA Resources

Arms and Interventions

Intervention Details:
    Drug: cholecalciferol
    capsules, 20 000IU, twice a week, 6 months duration

Outcome Measures

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

Secondary Outcome Measures :
  1. telomer length [ Time Frame: 6 months ]
  2. 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D-levels [ Time Frame: 6 months ]
  3. serum calcium, PTH, phosphate [ Time Frame: 6 months ]
  4. inflammatory markers and lipids [ Time Frame: 6 months ]

Eligibility Criteria

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

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

University Hospital of North Norway
Tromsø, Norway, 9037
Sponsors and Collaborators
University Hospital of North Norway
Norwegian Council on Cardiovascular diseases
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 Posted: December 17, 2008    Key Record Dates
Last Update Posted: November 3, 2011
Last Verified: November 2011

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