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OpenTrials
Completed

NCT Number: NCT00473317

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.

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Key information

Conditions

Vitamin D Deficiency Avitaminosis Deficiency Diseases Malnutrition Nutrition Disorders Nutritional and Metabolic Diseases

Age range

19 year–50 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Creighton University

Omaha, Nebraska, 68131, United States

About this study

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).

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

Sun Exposure

Behavioral

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).

Primary outcomes

  1. 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.

    Time frame: 1 week

Sponsors and collaborators

Lead sponsor

Creighton University

Other

Registry information

Important dates

Study start
2007
Primary completion
2007
Study completion
2007
First posted
May 15, 2007
Registry last updated
Apr 1, 2008

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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