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Completed

NCT Number: NCT00809744

Vitamin D AND Glucose Handling Evaluated by Glucose Clamp

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.

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Key information

Conditions

Insulin Sensitivity Glucose Metabolism Disorders Hyperinsulinism Insulin Resistance Intraocular Pressure Metabolic Diseases Nutritional and Metabolic Diseases

Age range

30 year–75 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

University Hospital of North Norway

Tromsø, 9037, Norway

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Cholecalciferol

Drug

capsules, 20 000IU, twice a week, 6 months duration

Primary outcomes

  1. insulin secretion and sensitivity as assessed by an hyperglycemic clamp

    Time frame: 6 months

  2. intraocular pressure

    Time frame: 6 months

Secondary outcomes

  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

Sponsors and collaborators

Lead sponsor

University Hospital of North Norway

Other

Collaborators

  • Norwegian Council on Cardiovascular diseases

Registry information

Official study title

Vitamin D AND Cardiovascular Disease

Acronym: D-clamp

Important dates

Study start
2008
Primary completion
2010
Study completion
2010
First posted
Dec 17, 2008
Registry last updated
Nov 3, 2011

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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