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Environmental Influences on Vitamin D Status (Alaska/Hawaii)

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ClinicalTrials.gov Identifier: NCT00780247
Recruitment Status : Completed
First Posted : October 27, 2008
Last Update Posted : October 27, 2008
Sponsor:
Collaborator:
Information provided by:

Study Description
Brief Summary:
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.

Condition or disease
Vitamin D Deficiency

Detailed Description:

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).

Study Design

Study Type : Observational
Actual Enrollment : 50 participants
Observational Model: Cohort
Time Perspective: Cross-Sectional
Official Title: Environmental Influences on Vitamin D Status
Study Start Date : July 2008
Primary Completion Date : August 2008
Study Completion Date : August 2008

Resource links provided by the National Library of Medicine

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

Groups and Cohorts

Group/Cohort
Alaska residents
50 "healthy" community dwelling males or females.
Hawaiian residents
50 "healthy" community dwelling males or females at each site


Outcome Measures

Primary Outcome Measures :
  1. To measure the prevailing 25D and Vitamin D levels in communities at diverse latitudes [ Time Frame: crosssectional ]

Secondary Outcome Measures :
  1. 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 ]
  2. 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 ]

Eligibility Criteria

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

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.

Criteria

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.
Contacts and Locations

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 ClinicalTrials.gov identifier (NCT number): NCT00780247


Locations
United States, Alaska
Alaska Kidney and Diabetes Associates
Anchorage, Alaska, United States, 99508
Sponsors and Collaborators
Creighton University
Procter and Gamble
Investigators
Principal Investigator: Laura A Armas, MD Creighton University
More Information

Responsible Party: Laura Armas, M D, Creighton University
ClinicalTrials.gov Identifier: NCT00780247     History of Changes
Other Study ID Numbers: Creighton6
WIRB approval 20080712
First Posted: October 27, 2008    Key Record Dates
Last Update Posted: October 27, 2008
Last Verified: October 2008

Keywords provided by Creighton University:
Vitamin D
Sun
Latitude
Vitamin D status

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