title: Skin color is relevant to vitamin D synthesis.
abstract: BACKGROUND
  Whether dark skin produces less vitamin D after UVB radiation than fair skin remains controversial.
  
  
  OBJECTIVE
  To compare 25-hydroxyvitamin D [25-(OH)-D] levels after a single UVB exposure in fair (phototype II-III) and black-skinned (phototype VI) volunteers.
  
  
  METHODS
  Fair-skinned volunteers (n = 20, 4 males/16 females, mean age: 23.2 years) and black-skinned (n = 11, 6 males/5 females, mean age: 23.8 years) received a single total body UVB exposure (0.022 J/cm(2)). The 25-(OH)-D levels were measured on days 0, 2 and 6.
  
  
  RESULTS
  On day 0, all volunteers were severely vitamin D deficient. On day 2, 25-(OH)-D levels of fair-skinned volunteers increased significantly (median: 11.9-13.3 ng/ml, p < 0.0001), but not in black-skinned people (median: 8.60-8.55 ng/ml, p = 0.843). Again, on day 6, 25-(OH)-D levels of fair-skinned volunteers increased significantly (median: 11.9-14.3 ng/ml, p < 0.0001), but not in black-skinned people (median: 8.60-9.57 ng/ml, p = 0.375).
  
  
  CONCLUSIONS
  This study suggests that skin pigmentation negatively influences vitamin D synthesis.
authors.affiliation: Department of Dermatology, University Hospital of Liège, Liège, Belgium.
authors.forename: F
authors.initials: F
authors.lastname: Libon
authors.forename: E
authors.initials: E
authors.lastname: Cavalier
authors.forename: A F
authors.initials: AF
authors.lastname: Nikkels
mesh_terms: D000328:Adult; D044383:Black People; D005260:Female; D006801:Humans; D008297:Male; D012867:Skin / Q000378:metabolism / Q000528:radiation effects*; D012880:Skin Pigmentation / Q000502:physiology*; D014466:Ultraviolet Rays; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000096:biosynthesis* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood; D044465:White People; D055815:Young Adult
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D