Sunlight Exposures Effect on Serum Vitamin D Levels

Not Applicable

Completed

• Conditions: Vitamin D Deficiency
• Interventions: Behavioral: Sun Exposure

• Registration Number: NCT00473317
• Lead Sponsor: Creighton University

Brief Summary

When people eat a meal, some, but not all of the calcium in that meal is absorbed, that is, moved into the bloodstream. When the skin is exposed to sunlight during summer months, Vitamin D is made there and then modified into more active forms by the liver and kidneys. These more active forms of Vitamin D improve calcium absorption. Many adults living in the U.S. have little or no sun exposure and are low in Vitamin D. We know that specific wavelengths of sunlight called Ultraviolet-B cause Vitamin D to be made in the skin.

Detailed Description

At the beginning of the study we will measure your height, weight, skin color, and draw blood to measure your blood levels of Vitamin D and 25-hydroxyvitamin D. Each subject will wear a swimming suit and be exposed to sunlight for 30 minutes total (15 minutes lying on back, 15 minutes lying on stomach).We will draw blood for Vitamin D and 25-hydroxyvitamin D on days 1,2,3,5, and 7 after sunlight exposure. There will be six blood draws for a total of 102 cc of blood drawn (about 3 ½ teaspoons drawn each time).

Study Timeline

• Study First Submitted: 2007-05-11
• Study First Submitted QC: 2007-05-11
• Study First Posted: 2007-05-15
• Study Start: 2007-07
• Primary Completion: 2007-09
• Study Completion: 2007-09
• Status Verified: 2008-03
• Last Update Submitted: 2008-03-30
• Last Update Posted: 2008-04-01

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 6

Inclusion Criteria

• healthy males or females ages19-50 with "light" skin (self-assessed as Fitzpatrick skin type I-III) with minimal sun exposure and exogenous sources of vitamin D.

Exclusion Criteria

• less than 16 oz milk per day, less than 10 hours of sun per week, no Vitamin D supplements, no anticonvulsants, no barbiturates, no steroids, no meds that increase photosensitivity, no granulomatous disease, no liver or kidney disease, no history of skin cancer, and BMI less than 30.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
1	Sun Exposure	All subjects in this study will be in the active arm

Primary Outcome Measures

Name	Time	Method
The goal of this study is to correlate vitamin D response and 25(OH)D response to sun exposure with most of the body (90 %) exposed to 0.25 hour of July sunlight at 41.2º N latitude and at approximately 1-2 pm in the afternoon.	1 week

Trial Locations

Locations (1)

Creighton University; 🇺🇸 Omaha, Nebraska, United States