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Vitamin D Binding Protein (Gc) Allele Variation Effects Response to Vitamin D Treatment (Gc)

This study has been completed.
Information provided by:
Creighton University Identifier:
First received: March 30, 2008
Last updated: April 1, 2008
Last verified: March 2008
We have just completed a randomized, clinical trial of 100,000 IU Vitamin D3 given as a single dose at the beginning of winter. We found a wide range of responses to the dose. This study proposes that genetic differences account for some of the variation in response of 25(OH)D levels after treatment with oral Vitamin D.

Vitamin D Status

Study Type: Observational
Study Design: Observational Model: Cohort
Time Perspective: Cross-Sectional
Official Title: Vitamin D Binding Protein (Gc) Allele Variation Effects Response to Vitamin D Treatment

Resource links provided by NLM:

Further study details as provided by Creighton University:

Primary Outcome Measures:
  • Gc concentration and phenotype [ Time Frame: at 1st visit ]

Enrollment: 29
Study Start Date: October 2007
Study Completion Date: January 2008
Primary Completion Date: January 2008 (Final data collection date for primary outcome measure)
All of the subjects will have measurements of Gc concentration and phenotype

Detailed Description:

We suspect that the wide range of response is effected by other factors such as variation in Vitamin D binding protein (the major transporter of Vitamin D metabolites).

Gc, also known as Vitamin D binding protein (DBP), group specific component, or Gc globulin, is a 52-58 kDa multifunctional plasma protein, synthesized in the liver. The gene encoding for Gc is located on chromosome 4, and three common co-dominant alleles give rise to three phenotypes (Gc1s, Gc1f, and Gc2). Gc binds actin, recruits neutrophil leukocytes and converts into a macrophage- and osteoclast- activating factor. It also is the major transporter of Vitamin D and its' metabolites. Lauridsen et al. showed that Gc phenotype correlates with 25(OH)D levels in a group of postmenopausal women.

This study proposes that Gc phenotype accounts for some of the variation in response of 25(OH)D levels after treatment with oral Vitamin D.


Ages Eligible for Study:   19 Years to 90 Years   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population
This study will include thirty males and females who took part in a previous study of a single oral dose of vitamin D.

Inclusion Criteria:

  • Must be willing to participate with an additional blood draw.
  • Must have been in the previous study.

Exclusion Criteria:

  • Will not be eligible if not a part of the previous study
  Contacts and Locations
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Please refer to this study by its identifier: NCT00650780

United States, Nebraska
Creighton University
Omaha, Nebraska, United States, 68131
Sponsors and Collaborators
Creighton University
Principal Investigator: Laura Armas, MD Creighton University
  More Information

Responsible Party: Laura Armas, Creighton University Identifier: NCT00650780     History of Changes
Other Study ID Numbers: Creighton4
Study First Received: March 30, 2008
Last Updated: April 1, 2008

Keywords provided by Creighton University:
Viatmin D, 25-hydroxyvitamin D, Vitamin D binding protein

Additional relevant MeSH terms:
Vitamin D
Growth Substances
Physiological Effects of Drugs
Bone Density Conservation Agents processed this record on May 23, 2017