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Environmental Influences on Vitamin D Status

NCT ID: NCT00780247

Last Updated: 2008-10-27

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Total Enrollment

50 participants

Study Classification

OBSERVATIONAL

Study Start Date

2008-07-31

Study Completion Date

2008-08-31

Brief Summary

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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

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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).

Conditions

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Vitamin D Deficiency

Keywords

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Vitamin D Sun Latitude Vitamin D status

Study Design

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Observational Model Type

COHORT

Study Time Perspective

CROSS_SECTIONAL

Study Groups

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Alaska residents

50 "healthy" community dwelling males or females.

No interventions assigned to this group

Hawaiian residents

50 "healthy" community dwelling males or females at each site

No interventions assigned to this group

Eligibility Criteria

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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.
Minimum Eligible Age

18 Years

Maximum Eligible Age

60 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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Procter and Gamble

INDUSTRY

Sponsor Role collaborator

Creighton University

OTHER

Sponsor Role lead

Responsible Party

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Creighton University

Principal Investigators

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Laura A Armas, MD

Role: PRINCIPAL_INVESTIGATOR

Creighton University

Locations

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Alaska Kidney and Diabetes Associates

Anchorage, Alaska, United States

Site Status

Countries

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United States

Other Identifiers

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WIRB approval 20080712

Identifier Type: -

Identifier Source: secondary_id

Creighton6

Identifier Type: -

Identifier Source: org_study_id