Sunlight Exposures Effect on Serum Vitamin D Levels

Creighton University

Status

Completed

Conditions

Vitamin D Deficiency

Treatments

Behavioral: Sun Exposure

Study type

Interventional

Funder types

Other

Identifiers

NCT00473317

Creighton3

Details and patient eligibility

About

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.

Full 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).

Enrollment

6 patients

Sex

All

Ages

19 to 50 years old

Volunteers

Accepts Healthy Volunteers

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.