Environmental Influences on Vitamin D Status — Alaska/Hawaii  

Vitamin D Deficiency Clinical Trial

Official title: Environmental Influences on Vitamin D Status

Status Completed

Clinical Trial 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.

Clinical Trial 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

Observational Model: Cohort, Time Perspective: Cross-Sectional

Related Conditions & MeSH terms

• Vitamin D Deficiency

• NCT number: NCT00780247
• Study type: Observational
• Source: Creighton University
• Status: Completed
• Phase: N/A
• Start date: July 2008
• Completion date: August 2008