Environmental Influences on Vitamin D Status
Alaska/Hawaii
2 other identifiers
observational
50
1 country
1
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.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P25-P50 for all trials
Started Jul 2008
Shorter than P25 for all trials
1 active site
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
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Study Timeline
Key milestones and dates
Study Start
First participant enrolled
July 1, 2008
CompletedPrimary Completion
Last participant's last visit for primary outcome
August 1, 2008
CompletedStudy Completion
Last participant's last visit for all outcomes
August 1, 2008
CompletedFirst Submitted
Initial submission to the registry
October 24, 2008
CompletedFirst Posted
Study publicly available on registry
October 27, 2008
CompletedOctober 27, 2008
October 1, 2008
1 month
October 24, 2008
October 24, 2008
Conditions
Keywords
Outcome Measures
Primary Outcomes (1)
To measure the prevailing 25D and Vitamin D levels in communities at diverse latitudes
crosssectional
Secondary Outcomes (2)
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.
cross sectional
To collect a blood sample for DNA analysis of inter-individual differences in Vitamin D metabolism (Gc or Vitamin D binding protein alleles).
cross sectional
Study Arms (2)
Alaska residents
50 "healthy" community dwelling males or females.
Hawaiian residents
50 "healthy" community dwelling males or females at each site
Eligibility Criteria
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.
You may qualify if:
- Able to consent and come for a study visit. Male or female males and females ages 18-60.
You may not qualify if:
- 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.
Contact the study team to confirm eligibility.
Sponsors & Collaborators
- Creighton Universitylead
- Procter and Gamblecollaborator
Study Sites (1)
Alaska Kidney and Diabetes Associates
Anchorage, Alaska, 99508, United States
MeSH Terms
Conditions
Condition Hierarchy (Ancestors)
Study Officials
- PRINCIPAL INVESTIGATOR
Laura A Armas, MD
Creighton University
Study Design
- Study Type
- observational
- Observational Model
- COHORT
- Time Perspective
- CROSS SECTIONAL
- Sponsor Type
- OTHER
Study Record Dates
First Submitted
October 24, 2008
First Posted
October 27, 2008
Study Start
July 1, 2008
Primary Completion
August 1, 2008
Study Completion
August 1, 2008
Last Updated
October 27, 2008
Record last verified: 2008-10