The Response of Serum 25-Hydroxyvitamin D to Incidental Ultraviolet Light Exposure

We will conduct a pilot study to investigate the ability to generate a dose-response curve
of serum 25-hydroxyvitamin D to incidental ultraviolet light exposure measured objectively
with a computerized personal ultraviolet light radiation dosimeter among 10 healthy
volunteers in New Mexico where the population is highly exposed to solar UV radiation.
During the follow-up period we will collect solar exposure data through a self-reported sun
exposure diary, in tandem with objective UV dosimeter data, and will collect blood samples
for serum measurements. We will carry out clinical measurements of serum vitamin D,
parathyroid hormone, and calcium and phosphorus ions. We will analyze the correlation
between the vitamin D and the recorded UV exposure in order to evaluate physiological
changes due to solar exposure. This pilot study is important for melanoma prevention as
there is currently confusion among the public as to how much sun is needed for vitamin D
production and when too much sun exposure will increase risk for developing melanoma.

Expected benefits of this study to the participants include obtaining an objective measure
of daily ultraviolet exposure and vitamin D status and the possible need for
supplementation. Expected benefits to society include determining a dose-response of vitamin
D to ultraviolet light that will enhance our understanding of the balance between necessary
and harmful ultraviolet exposure. The results generated in this pilot study could provide a
scientific basis for designing a larger study to develop effective primary prevention
against cutaneous malignant melanoma.

This pilot study will investigate the ability to generate a dose-response curve of serum
25-hydroxyvitamin D to incidental ultraviolet light exposure measured objectively with a
computerized personal UVR dosimeter. The knowledge obtained will provide important pilot
data a larger NIH grant to estimate the risk-benefit of solar exposure and serum vitamin D
in the development and prevention of cutaneous melanoma.

Inclusion Criteria:

1. Light-skinned volunteers (Caucasians including Hispanics with slightly darker
complexion)

2. 18 years of age (5 men and 5 women)

3. Resident in the State of New Mexico

4. Indoor workers with no significant history of prolonged, excessive sun exposure

5. Willing to have a monthly blood draw

6. Willing to fill out the sun diary every day on different indoor/outdoor activities.

7. During the project time period potential pregnancy of women volunteers would change
the risk category of the participants, and that is a reportable event to UNM HSC HRRC
and the Clinical Trial Office.

Further explanation of the inclusion criteria:

This pilot study is intended to evaluate the dose-response associations between measured
UV exposure and individual serum 25 (OH)-vitamin D levels. To date, there is little data
and a great deal of mis-information about vitamin D. Caucasians have a variety of skin
types and melanin production. This pilot study is unfunded and we know that there is
extreme heterogeneity among Caucasians in their absorption of UVB and subsequent synthesis
of vitamin D. Among our volunteers 2 participants with Hispanic ethnicity are represented
as well. Darker-skinned individuals, such as African Americans, produce considerably less
vitamin D, based on the bone health literature. Inclusion of African Americans will be
critical in the future as we develop our understanding of the relationship between vitamin
D and UV exposure. Our collaborator, Elizabeth Jacobs at the University of Arizona, is
currently conducting a pilot study to evaluate UV and serum vitamin D among individuals
with darker pigmentation. The motivation for our pilot study has to do with the balance
between vitamin D and sun exposure as a risk-benefit assessment for the development of
melanoma. Asians and African Americans do develop melanoma, but at a rate ten times less
than Caucasians and it does not appear to be related to sun exposure; thus, to include
them at this time would not allow us to focus on the medically-related issue.

Exclusion Criteria:

1. Diet high in oily fish (e.g. eating cod liver or sardines oil conserved products more
than 2-3 times/week)

2. Oral vitamin D supplementation (over 1,000 IU/day amount)

3. Tanning bed use.

4. Existing pregnancy