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Validation of a Method to Predict Serum Vitamin D from Sun Exposure, Skin Reflectance & Dietary Intake in Overweight and Obese Subjects
Author(s) -
Piccolo Brian D,
Hall Laura,
Stephensen Charles,
Gertz Erik,
Woodhouse Leslie,
Souza Elaine,
Keim Nancy,
Adams Sean,
Van Loan Marta
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.996.7
Subject(s) - vitamin d and neurology , overweight , sunlight , medicine , reflectivity , vitamin , zoology , sun exposure , endocrinology , obesity , biology , physics , dermatology , astronomy , optics
Measurement of sunlight, a major contributor to serum vitamin D, is rarely done. We evaluated a model to predict serum vitamin D from sun exposure, skin reflectance & dietary intake in 63 overweight and obese men and women consuming a diet of known vitamin D content. Sun exposure was measured bi‐weekly from sun exposure logs that included date, time of day, location, activity, minutes in direct sun, clothing worn, and sunscreen use. UV‐B radiation measured by UV‐B Broadband Pyranometer and converted to J/m 2 . Skin reflectance was measured using a Minolta 2500d spectrophotometer. Serum 25(OH)D, was measured by RIA. The Hall et al. model incorporates total energy from sun exposure, skin reflectance, dietary vitamin D, and season to predict serum vitamin D. The association between actual serum 25(OH)D and predicted serum 25(OH)D was r = 0.071 (p < 0.0196). We found a significant positive bias (p < 0.0001) in the predicted 25(OH)D compared to actual serum 25(OH)D; the positive bias increased as serum 25(OH)D values increased. These results suggest the need for a new model to estimate serum vitamin D in overweight and obese populations. Funding: National Dairy Council; USDA, ARS, WHNRC; Dairy Council of California; CTSC, University of California (1M01RR19975‐01), National Center for Medical Research (UL1 RR024146 )