Environmental Influences on Vitamin D Status
- Conditions
- Vitamin D Deficiency
- Registration Number
- NCT00780247
- Lead Sponsor
- Creighton University
- 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.
- 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).
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- All
- Target Recruitment
- 50
- Able to consent and come for a study visit. Male or female males and females ages 18-60.
- 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.
Study & Design
- Study Type
- OBSERVATIONAL
- Study Design
- Not specified
- Primary Outcome Measures
Name Time Method To measure the prevailing 25D and Vitamin D levels in communities at diverse latitudes crosssectional
- Secondary Outcome Measures
Name Time Method 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
Trial Locations
- Locations (1)
Alaska Kidney and Diabetes Associates
🇺🇸Anchorage, Alaska, United States