This site became the new on June 19th. Learn more.
Show more Menu IMPORTANT: Listing of a study on this site does not reflect endorsement by the National Institutes of Health. Talk with a trusted healthcare professional before volunteering for a study. Read more... Menu IMPORTANT: Talk with a trusted healthcare professional before volunteering for a study. Read more... Menu
Give us feedback

Environmental & Genetic Influences on Vitamin D Status

This study has been completed.
Procter and Gamble
Information provided by:
Creighton University Identifier:
First received: August 30, 2010
Last updated: September 23, 2010
Last verified: September 2010
The purpose of this study is to determine the effect of environmental and genetic influences on Vitamin D status.

Vitamin D Deficiency

Study Type: Observational
Study Design: Observational Model: Cohort
Time Perspective: Cross-Sectional
Official Title: Environmental & Genetic Influences on Vitamin D Status

Resource links provided by NLM:

Further study details as provided by Creighton University:

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

Secondary Outcome Measures:
  • 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

Enrollment: 40
Study Start Date: August 2010
Study Completion Date: August 2010
Primary Completion Date: August 2010 (Final data collection date for primary outcome measure)
Sun exposed people
Sun exposure >3 hours daily for at least 5 days weekly for the last 3 months.

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.

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.
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: 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
  More Information

Responsible Party: Laura Armas, Creighton University Identifier: NCT01208636     History of Changes
Other Study ID Numbers: Creighton9
Study First Received: August 30, 2010
Last Updated: September 23, 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 processed this record on September 20, 2017