title: Ultraviolet-B radiation increases serum 25-hydroxyvitamin D levels: the effect of UVB dose and skin color.
abstract: BACKGROUND
  Ultraviolet (UV)-B light increases vitamin D levels, but the dose response and the effect of skin pigmentation have not been well characterized.
  
  
  OBJECTIVE
  We sought to define the relationship between UVB exposure and 25-hydroxyvitamin D (25-OH-D) concentrations as a function of skin pigmentation.
  
  
  METHODS
  Seventy two participants with various skin tones had 90% of their skin exposed to UVB light (20-80 mJ/cm2) 3 times a week for 4 weeks. Serum 25-OH-D was measured weekly.
  
  
  RESULTS
  Eighty percent of the variation in treatment response was explained by UVB dose and skin tone. Therapeutically important changes in 25-OH-D were achieved with minimal tanning.
  
  
  CONCLUSIONS
  Four weeks was not long enough to reach a steady state at the higher dose rates.
  
  
  CONCLUSIONS
  The response of 25-OH-D levels to UVB light is dependent on skin pigmentation and the amount of UVB given, and useful increases in vitamin D status can be achieved by defined UVB doses small enough to produce only minimal tanning.
authors.affiliation: Creighton University Medical Center, Omaha, Nebraska 68131, USA. larmas@creighton.edu
authors.forename: Laura A G
authors.initials: LA
authors.lastname: Armas
authors.forename: Susan
authors.initials: S
authors.lastname: Dowell
authors.forename: Mohammed
authors.initials: M
authors.lastname: Akhter
authors.forename: Sowjanya
authors.initials: S
authors.lastname: Duthuluru
authors.forename: Christopher
authors.initials: C
authors.lastname: Huerter
authors.forename: Bruce W
authors.initials: BW
authors.lastname: Hollis
authors.forename: Richard
authors.initials: R
authors.lastname: Lund
authors.forename: Robert P
authors.initials: RP
authors.lastname: Heaney
mesh_terms: D000328:Adult; D002112:Calcifediol / Q000097:blood*; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012867:Skin / Q000378:metabolism* / Q000528:radiation effects*; D012880:Skin Pigmentation / Q000502:physiology* / Q000528:radiation effects; D014467:Ultraviolet Therapy; D014808:Vitamin D Deficiency / Q000097:blood
chemical_list: D002112:Calcifediol