Environmental Influences on Vitamin D Status (Alaska/Hawaii)

This study has been completed.
Sponsor:
Collaborator:
Procter and Gamble
Information provided by:
Creighton University
ClinicalTrials.gov Identifier:
NCT00780247
First received: October 24, 2008
Last updated: NA
Last verified: October 2008
History: No changes posted

October 24, 2008
October 24, 2008
July 2008
August 2008   (final data collection date for primary outcome measure)
To measure the prevailing 25D and Vitamin D levels in communities at diverse latitudes [ Time Frame: crosssectional ] [ Designated as safety issue: No ]
Same as current
No Changes Posted
  • 2. To collect information on variables that influence Vitamin D status such to collect information on skin color, history of sun exposure and sunscreen use, diet history, vitamin and calcium supplements used, and BMI. [ Time Frame: cross sectional ] [ Designated as safety issue: No ]
  • To collect a blood sample for DNA analysis of inter-individual differences in Vitamin D metabolism (Gc or Vitamin D binding protein alleles). [ Time Frame: cross sectional ] [ Designated as safety issue: No ]
Same as current
Not Provided
Not Provided
 
Environmental Influences on Vitamin D Status
Environmental Influences on Vitamin D Status

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. However, the relative influences of each are largely unknown and we cannot reliably answer the question of how much sun exposure an individual needs at various latitudes and at various seasons in order to ensure normal vitamin D status.

Purpose of the study: To determine the effect of environmental influences on Vitamin D status.

Specific Aims

  1. To measure the prevailing 25D and Vitamin D levels in communities at diverse latitudes (Alaska and Hawaii).
  2. To collect information on variables that influence Vitamin D status such as skin color, history of sun exposure and sunscreen use, diet history, vitamin and calcium supplements used, and BMI.
  3. To collect typical food samples from the region for future analysis of their Vitamin D and 25D content.
  4. To collect a blood sample for DNA analysis of inter-individual differences in Vitamin D metabolism (Gc or Vitamin D binding protein alleles).
Observational
Observational Model: Cohort
Time Perspective: Cross-Sectional
Not Provided
Not Provided
Non-Probability Sample

Age of Subjects: The subjects will be between ages 18-60. The upper age is limited to age 60 as aging skin is less able to make vitamin D, therefore a separate study of elderly people would be more appropriate.

Racial and Ethnic Origin: Both sites have a diverse ethnic and racial population and the subjects will be as representative of the population as possible.

Vitamin D Deficiency
Not Provided
  • Alaska residents
    50 "healthy" community dwelling males or females.
  • Hawaiian residents
    50 "healthy" community dwelling males or females at each site
Not Provided

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Completed
50
August 2008
August 2008   (final data collection date for primary outcome measure)

Inclusion Criteria:

  • Able to consent and come for a study visit. Male or female males and females ages 18-60.

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.
Both
18 Years to 60 Years
Yes
Contact information is only displayed when the study is recruiting subjects
United States
 
NCT00780247
Creighton6, WIRB approval 20080712
No
Laura Armas, M D, Creighton University
Creighton University
Procter and Gamble
Principal Investigator: Laura A Armas, MD Creighton University
Creighton University
October 2008

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP