Environmental & Genetic Influences on Vitamin D Status

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01208636
Recruitment Status : Completed
First Posted : September 24, 2010
Last Update Posted : September 24, 2010
Procter and Gamble
Information provided by:
Creighton University

Brief Summary:
The purpose of this study is to determine the effect of environmental and genetic influences on Vitamin D status.

Condition or disease
Vitamin D Deficiency

Detailed Description:
Vitamin D deficiency is a common problem. The principal source of vitamin D for humans is solar exposure, with cutaneous synthesis of vitamin D by photoconversion of 7-dehydrocholesterol in the skin to pre-vitamin D3. Latitude, altitude, season, skin pigmentation, and age are recognized factors that influence how much vitamin D can be made by solar exposure. Surprisingly, Vitamin D deficiency has been described in people dwelling in southern Florida and in surfers in Hawaii. We hypothesize that genetic variations in vitamin metabolism accounts for these differences.

Study Type : Observational
Actual Enrollment : 40 participants
Observational Model: Cohort
Time Perspective: Cross-Sectional
Official Title: Environmental & Genetic Influences on Vitamin D Status
Study Start Date : August 2010
Actual Primary Completion Date : August 2010
Actual Study Completion Date : August 2010

Resource links provided by the National Library of Medicine

Drug Information available for: Vitamin D
U.S. FDA Resources

Sun exposed people
Sun exposure >3 hours daily for at least 5 days weekly for the last 3 months.

Primary Outcome Measures :
  1. 25(OH)D levels [ Time Frame: 1 month ]
    25(OH)D levels were measured at the only visit

Secondary Outcome Measures :
  1. Genetic testing of 13 candidate genes [ Time Frame: 1 month ]
    13 candidate genes were tested and their relationship to 25(OH)D examined.

Biospecimen Retention:   Samples With DNA
Blood was obtained for genetic testing of selected 13 candidate genes important for vitamin D metabolism

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 60 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population

This study will include 50 "healthy" unrelated community dwelling males or females.

The subjects will be between ages 18-60.


Inclusion Criteria:

  • Able to consent and come for a study visit.
  • Male or female between ages 18-60.
  • Sun exposure >3 hours daily for at least 5 days weekly for the last 3 months.

Exclusion Criteria:

  • Unable to consent or come to a visit
  • Taking Vitamin D supplements, anticonvulsants, barbiturates, steroids, having granulomatous disease, or liver or kidney disease as these medications and conditions interfere with Vitamin D metabolism.
  • Related to another participant by blood.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01208636

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

Responsible Party: Laura Armas, Creighton University Identifier: NCT01208636     History of Changes
Other Study ID Numbers: Creighton9
First Posted: September 24, 2010    Key Record Dates
Last Update Posted: September 24, 2010
Last Verified: September 2010

Keywords provided by Creighton University:
Vitamin D deficiency

Additional relevant MeSH terms:
Vitamin D Deficiency
Deficiency Diseases
Nutrition Disorders
Vitamin D
Growth Substances
Physiological Effects of Drugs
Bone Density Conservation Agents