Date of Award

12-2001

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Food Science and Human Nutrition

Advisor

Susan S. Sullivan

Second Committee Member

Adrienne A. White

Third Committee Member

William Halteman

Abstract

Sunlight is a major contributor to an individual's vitamin D status. Determinants of sun exposure have been used in conjunction with dietary data to study the effect of sunlight on bone health of elderly populations. Sun-exposure questionnaires to assess vitamin D status have not been utilized or tested in populations of children in the United States. This is the first questionnaire, used in accordance with vitamin D research, to be tested against an objective measure of sun exposure and to account for diurnal variation in ultraviolet B (UVB) ray strength. The objective of this study was to develop and validate a sun-exposure questionnaire for adolescent girls and to further investigate the potential for skin synthesis of previtamin Dg (preD3) in northern climates. Thirty-five girls (ages 9-15) from northeastern Maine wore a polysulphone (PS) film badge for one day. The sun-exposure questionnaire was administered the following day. Minutes spent outdoors during each hour of the day were corrected for the strength of the UVB rays during that hour. The correction. factor was established using UVB data generated from a USDA UVB Monitoring Site. Corrected minutes were compared with PS badge readings for each subject. A series of PS badges and ampules containing 7dehydrocholesterol were exposed each hour of the day to further investigate the effect of time of day on cutaneous preD3 synthesis. Subject self-reported minutes outdoors, corrected for the time of day, strongly correlated with the change in absorbance (AA) of PS badges (~0.71, p=0.000). In conclusion, relative to each other, adolescent girls were able to report time spent outdoors, and time of day spent outdoors is a crucial component of a sun exposure questionnaire. Because daily UVB data is available in virtually any locale in the United States, the questionnaire and the correction factor for the time of day can be easily adapted for use in a variety of research settings.

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