Sunlight Exposures Effect on Serum Vitamin D Levels

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.

Study Overview

• Status: Completed
• Conditions: Vitamin D Deficiency
• Intervention / Treatment: Behavioral: Sun Exposure

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 Type: Interventional
• Enrollment (Actual): 6
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Nebraska
    • Omaha, Nebraska, United States, 68131
      • Creighton University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 19 years to 50 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

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 Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: 1; All subjects in this study will be in the active arm	Behavioral: Sun Exposure; 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).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
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

Collaborators and Investigators

• Sponsor: Creighton University
• Investigators: Principal Investigator: Laura A Armas, MD, Creighton University

Study record dates

Study Major Dates

• Study Start: July 1, 2007
• Primary Completion (Actual): September 1, 2007
• Study Completion (Actual): September 1, 2007

Study Registration Dates

• First Submitted: May 11, 2007
• First Submitted That Met QC Criteria: May 11, 2007
• First Posted (Estimate): May 15, 2007

Study Record Updates

• Last Update Posted (Estimate): April 1, 2008
• Last Update Submitted That Met QC Criteria: March 30, 2008
• Last Verified: March 1, 2008

More Information

Terms related to this study

• Keywords: Vitamin D; UVB; sunlight
• Additional Relevant MeSH Terms: Nutrition Disorders; Avitaminosis; Deficiency Diseases; Malnutrition; Vitamin D Deficiency
• Other Study ID Numbers: Creighton3