Duration of Vitamin D Stores After Prolonged Vitamin D Substitution

Obesity Clinical Trial

Official title:

Duration of Vitamin D Stores After Prolonged Vitamin D Substitution

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT01729013
• Other study ID #: Tromsø-Endo-2012-2
• Status: Completed
• Phase: N/A
• First received: November 13, 2012
• Last updated: September 18, 2015
• Start date: November 2012
• Est. completion date: August 2015

Study information

• Verified date: September 2015
• Source: University of Tromso
• Contact: n/a
• Is FDA regulated: No
• Health authority: Norway:National Committee for Medical and Health Research Ethics
• Study type: Observational

Clinical Trial 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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 78
• Est. completion date: August 2015
• Est. primary completion date: May 2015
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Both
• Age group: 25 Years to 85 Years

Eligibility

Inclusion Criteria:

• previously participated in a vitamin D study

Exclusion Criteria:

• pregnancy

Study Design

Observational Model: Cohort, Time Perspective: Prospective

Related Conditions & MeSH terms

• Obesity

Locations

Country	Name	City	State
Norway	University of Tromsø	Tromsø

Sponsors (1)

Lead Sponsor	Collaborator
University of Tromso

Country where clinical trial is conducted

Norway, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	half-life of serum 25-hydroxyvitamin D		up to 12 months	No