Environmental Influences on Vitamin D Status - Full Text View

Sponsor:	Creighton University
Collaborator:	Procter and Gamble
Information provided by:	Creighton University
ClinicalTrials.gov Identifier:	NCT00780247

Purpose

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
Vitamin D Deficiency

Study Type:	Observational
Study Design:	Cohort, Cross-Sectional
Official Title:	Environmental Influences on Vitamin D Status

Resource links provided by NLM:

Drug Information available for: Vitamin D

U.S. FDA Resources

Further study details as provided by Creighton University:

Primary Outcome Measures:

To measure the prevailing 25D and Vitamin D levels in communities at diverse latitudes [ Time Frame: crosssectional ] [ Designated as safety issue: No ]

Secondary Outcome Measures:

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 ]

Biospecimen Retention: None Retained

Biospecimen Description:

Enrollment:	50
Study Start Date:	July 2008
Study Completion Date:	August 2008
Primary Completion Date:	August 2008 (Final data collection date for primary outcome measure)

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

Detailed Description:

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

Specific Aims

To measure the prevailing 25D and Vitamin D levels in communities at diverse latitudes (Alaska and Hawaii).
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.
To collect typical food samples from the region for future analysis of their Vitamin D and 25D content.
To collect a blood sample for DNA analysis of inter-individual differences in Vitamin D metabolism (Gc or Vitamin D binding protein alleles).

Eligibility

Ages Eligible for Study:	18 Years to 60 Years
Genders Eligible for Study:	Both
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

Please refer to this study by its ClinicalTrials.gov identifier: 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

No publications provided

Responsible Party:	Creighton University ( Laura Armas, M D )
Study ID Numbers:	Creighton6, WIRB approval 20080712
Study First Received:	October 24, 2008
Last Updated:	October 24, 2008
ClinicalTrials.gov Identifier:	NCT00780247 History of Changes
Health Authority:	United States: Institutional Review Board

Keywords provided by Creighton University:

Vitamin D
Sun
Latitude
Vitamin D status

Additional relevant MeSH terms:

Vitamin D Deficiency
Avitaminosis
Growth Substances
Physiological Effects of Drugs
Ergocalciferols
Bone Density Conservation Agents
Pharmacologic Actions

Malnutrition
Vitamin D
Vitamins
Nutrition Disorders
Micronutrients
Deficiency Diseases

ClinicalTrials.gov processed this record on February 08, 2010