Duration of Vitamin D Stores After Prolonged Vitamin D Substitution

This study is currently recruiting participants. (see Contacts and Locations)
Verified August 2013 by University of Tromso
Sponsor:
Information provided by (Responsible Party):
University of Tromso
ClinicalTrials.gov Identifier:
NCT01729013
First received: November 13, 2012
Last updated: August 16, 2013
Last verified: August 2013

November 13, 2012
August 16, 2013
November 2012
November 2014   (final data collection date for primary outcome measure)
half-life of serum 25-hydroxyvitamin D [ Time Frame: up to 12 months ] [ Designated as safety issue: No ]
Same as current
Complete list of historical versions of study NCT01729013 on ClinicalTrials.gov Archive Site
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Duration of Vitamin D Stores After Prolonged Vitamin D Substitution
Duration of Vitamin D Stores After Prolonged Vitamin D Substitution

Ingested or skin produced vitamin D is either hydroxylated in the liver to 25-hydroxyvitamin D (25(OH)D), metabolized and excreted in the urine, or stored in adipose and other tissues. The capacity for vitamin D storage in adipose tissue is not known, nor the importance of such storage which may potentially be of vital importance when intake or solar exposure is limited. In the present study we will include 76 subjects who have participated in an intervention study with vitamin D (20.000 IU per week) versus placebo for the prevention of type 2 diabetes, and who have completed the study after 5 years or who have been excluded because of diagnosed type 2 diabetes or for other reasons. If vitamin D is stored to any extent in the body the subjects given 20.000 IU vitamin D per week for 2-5 years will have a considerable amount of stored vitamin D and accordingly, a slow decline in serum 25(OH)D during the following year without vitamin D substitution, which will be measured in the present study. If our hypothesis is correct, that vitamin D can be stored in significant amounts when the supply is abundant; current advice on vitamin D supplementation mainly during winter should be changed to "year around" in order to build up sufficient stores for the months without sufficient sun light.

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Observational
Observational Model: Cohort
Time Perspective: Prospective
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Retention:   Samples Without DNA
Description:

blood samples and fat biopsy

Non-Probability Sample

Subjects who have previously participated in a vitamin D study

Obesity
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  • subjects previously given placebo
  • subjects previously given vitamin D
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*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Recruiting
100
November 2015
November 2014   (final data collection date for primary outcome measure)

Inclusion Criteria:

  • previously participated in a vitamin D study

Exclusion Criteria:

  • pregnancy
Both
25 Years to 85 Years
Yes
Contact: rolf jorde, professor 4777626827 rolf.jorde@unn.no
Norway
 
NCT01729013
Tromsø-Endo-2012-2
No
University of Tromso
University of Tromso
Not Provided
Principal Investigator: rolf jorde, professor University of Tromso
University of Tromso
August 2013

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP