Environmental & Genetic Influences on Vitamin D Status

September 23, 2010 updated by: Creighton University
The purpose of this study is to determine the effect of environmental and genetic influences on Vitamin D status.

Study Overview

Status

Completed

Conditions

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

Enrollment (Actual)

40

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

  • United States
    • Nebraska
      • Omaha, Nebraska, United States, 68131
        • Creighton University

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

18 years to 60 years (Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

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.

Description

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.

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

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
25(OH)D levels
Time Frame: 1 month
25(OH)D levels were measured at the only visit
1 month

Secondary Outcome Measures

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

Collaborators and Investigators

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

Sponsor

Creighton University

Collaborators

Procter and Gamble

Investigators

  • Principal Investigator: Laura Armas, MD, Creighton University

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

August 1, 2010

Primary Completion (Actual)

August 1, 2010

Study Completion (Actual)

August 1, 2010

Study Registration Dates

First Submitted

August 30, 2010

First Submitted That Met QC Criteria

September 23, 2010

First Posted (Estimate)

September 24, 2010

Study Record Updates

Last Update Posted (Estimate)

September 24, 2010

Last Update Submitted That Met QC Criteria

September 23, 2010

Last Verified

September 1, 2010

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • Creighton9

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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