Normal vitamin D levels can be maintained despite rigorous photoprotection: six years' experience with xeroderma pigmentosum.
BACKGROUND
Although sun protection is advocated for skin cancer prevention, sunlight is also important in generation of vitamin D in the skin. There is concern that sun protection may result in an abnormally low level of vitamin D.


OBJECTIVE
To assess the risk of vitamin D deficiency in a sunlight-deprived population, we studied eight ambulatory patients with xeroderma pigmentosum (XP) who practiced intensive sun protection during a chemoprevention study of oral isotretinoin.


METHODS
We surveyed the patients to determine the extent of sun protection and vitamin D intake and measured the serum levels of two vitamin D metabolites (25-hydroxyvitamin D [25-OHD] and 1,25-dihydroxyvitamin D [1,25-(OH)2D]), calcium, and parathyroid hormone during 6 years.


RESULTS
The patients all wore protective clothing and sunscreens when outdoors. Estimated mean vitamin D intake was normal. The mean values of serum 25-OHD were low normal, but 1,25-(OH)2D, calcium, ionized calcium and parathyroid hormone levels were normal. Lack of seasonal variation in serum 25-OHD indicated rigorous photoprotection.


CONCLUSIONS
Despite rigorous sun protection normal vitamin D levels can be maintained in ambulatory patients with XP.
Sollitto
R B
RB
Dermatology Clinical Research Unit, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
Kraemer
K H
KH
DiGiovanna
J J
JJ
D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D000553:Ambulatory Care; D002118:Calcium / Q000097:blood; D018890:Chemoprevention; D004100:Dihydroxycholecalciferols / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015474:Isotretinoin / Q000008:administration & dosage / Q000627:therapeutic use; D007641:Keratolytic Agents / Q000008:administration & dosage / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D011481:Protective Clothing; D012307:Risk Factors; D012621:Seasons; D012867:Skin / Q000378:metabolism / Q000528:radiation effects; D013472:Sunlight; D013473:Sunscreening Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D014807:Vitamin D / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000096:biosynthesis / Q000097:blood* / Q000528:radiation effects; D014808:Vitamin D Deficiency / Q000209:etiology; D014983:Xeroderma Pigmentosum / Q000097:blood / Q000517:prevention & control*
D004100:Dihydroxycholecalciferols; D007641:Keratolytic Agents; D010281:Parathyroid Hormone; D013473:Sunscreening Agents; D014807:Vitamin D; C097949:1,25-dihydroxyvitamin D; D015474:Isotretinoin; D002118:Calcium