Duration of Vitamin D Stores After Prolonged Vitamin D Substitution

NCT ID: NCT01729013

Last Updated: 2015-09-22

Basic Information

• Recruitment Status: COMPLETED
• Total Enrollment: 78 participants
• Study Classification: OBSERVATIONAL
• Study Start Date: 2012-11-30
• Study Completion Date: 2015-08-31

Brief 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

Obesity

Study Design

• Observational Model Type: COHORT
• Study Time Perspective: PROSPECTIVE

Study Groups

subjects previously given placebo

No interventions assigned to this group

subjects previously given vitamin D

No interventions assigned to this group

Eligibility Criteria

Inclusion Criteria

• previously participated in a vitamin D study

Exclusion Criteria

• pregnancy

• Minimum Eligible Age: 25 Years
• Maximum Eligible Age: 85 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

University of Tromso

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

rolf jorde, professor

Role: PRINCIPAL_INVESTIGATOR

University of Tromso

Locations

University of Tromsø

Tromsø, Tromsø, Norway

Countries

Norway

References

Martinaityte I, Kamycheva E, Didriksen A, Jakobsen J, Jorde R. Vitamin D Stored in Fat Tissue During a 5-Year Intervention Affects Serum 25-Hydroxyvitamin D Levels the Following Year. J Clin Endocrinol Metab. 2017 Oct 1;102(10):3731-3738. doi: 10.1210/jc.2017-01187.

Reference Type: DERIVED

PMID: 28973683 (View on PubMed)

Other Identifiers

Tromsø-Endo-2012-2

Identifier Type: -

Identifier Source: org_study_id