NORMAL VITAMIN-D LEVELS CAN BE MAINTAINED DESPITE RIGOROUS PHOTOPROTECTION - 6 YEARS EXPERIENCE WITH XERODERMA-PIGMENTOSUM

Background: Although sun protection is advocated for skin cancer preve ntion, sunlight is also important in generation of vitamin D in the sk in. There is concern that sun protection may result in an abnormally l ow level of vitamin D. Objective: To assess the risk of vitamin D defi ciency in a sunlight-deprived population, we studied eight ambulatory patients with xeroderma pigmentosum (XP) who practiced intensive sun p rotection during a chemoprevention study of oral isotretinoin. Methods : We surveyed the patients to determine the extent of sun protection a nd vitamin D intake and measured the serum levels of two vitamin D met abolites (25-hydroxyvitamin D [25-OHD] and 1,25-dihydroxyvitamin D [1, 25-(OH)(2)D]), calcium, and parathyroid hormone during 6 years, Result s: The patients all wore protective clothing and sunscreens when outdo ors, Estimated mean vitamin D intake was normal. The mean values of se rum 25-OHD were low normal, but 1,25-(OH)(2)D, calcium, ionized calciu m and parathyroid hormone levels were normal. Lack of seasonal variati on in serum 25-OHD indicated rigorous photoprotection. Conclusion: Des pite rigorous sun protection normal vitamin D levels can be maintained in ambulatory patients with XP.