Duration of Vitamin D Stores After Prolonged Vitamin D Substitution

September 18, 2015 updated by: University of Tromso
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.

Study Overview

Status

Completed

Conditions

Study Type

Observational

Enrollment (Actual)

78

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Norway
      • Tromsø, Norway, 9037
        • University of Tromsø

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

25 years to 85 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Subjects who have previously participated in a vitamin D study

Description

Inclusion Criteria:

  • previously participated in a vitamin D study

Exclusion Criteria:

  • pregnancy

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
subjects previously given placebo
subjects previously given vitamin D

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
half-life of serum 25-hydroxyvitamin D
Time Frame: up to 12 months
up to 12 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Tromso

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

November 1, 2012

Primary Completion (Actual)

May 1, 2015

Study Completion (Actual)

August 1, 2015

Study Registration Dates

First Submitted

November 13, 2012

First Submitted That Met QC Criteria

November 19, 2012

First Posted (Estimate)

November 20, 2012

Study Record Updates

Last Update Posted (Estimate)

September 22, 2015

Last Update Submitted That Met QC Criteria

September 18, 2015

Last Verified

September 1, 2015

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • Tromsø-Endo-2012-2

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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