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Duration of Vitamin D Stores After Prolonged Vitamin D Substitution

NCT01729013 · Status: COMPLETED · Type: OBSERVATIONAL · Enrollment: 78

Last updated 2015-09-22

No results posted yet for this study

Summary

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.

Conditions

Sponsors & Collaborators

  • University of Tromso

    lead OTHER

Principal Investigators

  • rolf jorde, professor · University of Tromso

Eligibility

Min Age
25 Years
Max Age
85 Years
Sex
ALL
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2012-11-30
Primary Completion
2015-05-31
Completion
2015-08-31

Countries

  • Norway

Study Locations

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Entities

Diseases

Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT01729013 on ClinicalTrials.gov