title: Vitamin D and prevention of colorectal cancer.
abstract: BACKGROUND
  Inadequate photosynthesis or oral intake of Vitamin D are associated with high incidence rates of colorectal cancer, but the dose-response relationship has not been adequately studied.
  
  
  METHODS
  Dose-response gradients from observational studies of Vitamin D intake and serum 25-hydroxyvitamin D were plotted as trend lines. The point on each linear trend line corresponding to an odds ratio of 0.50 provided the prediagnostic Vitamin D intake or 25-hydroxyvitamin D concentration associated with 50% lower risk compared to <100IU/day Vitamin D or <13ng/ml serum 25-hydroxyvitamin D. Medians of these values were determined.
  
  
  RESULTS
  Overall, individuals with >or=1000IU/day oral Vitamin D (p<0.0001) or >or=33ng/ml (82nmol/l) serum 25-hydroxyvitamin D (p<0.01) had 50% lower incidence of colorectal cancer compared to reference values.
  
  
  CONCLUSIONS
  Intake of 1000IU/day of Vitamin D, half the safe upper intake established by the National Academy of Sciences, was associated with 50% lower risk. Serum 25-hydroxyvitamin D of 33ng/ml, which is known to be safe, also was associated with 50% lower risk. Prompt public health action is needed to increase intake of Vitamin D(3) to 1000IU/day, and to raise 25-hydroxyvitamin D by encouraging a modest duration of sunlight exposure.
authors.affiliation: Naval Health Research Center, San Diego, CA 92186, USA.
authors.forename: Edward D
authors.initials: ED
authors.lastname: Gorham
authors.forename: Cedric F
authors.initials: CF
authors.lastname: Garland
authors.forename: Frank C
authors.initials: FC
authors.lastname: Garland
authors.forename: William B
authors.initials: WB
authors.lastname: Grant
authors.forename: Sharif B
authors.initials: SB
authors.lastname: Mohr
authors.forename: Martin
authors.initials: M
authors.lastname: Lipkin
authors.forename: Harold L
authors.initials: HL
authors.lastname: Newmark
authors.forename: Edward
authors.initials: E
authors.lastname: Giovannucci
authors.forename: Melissa
authors.initials: M
authors.lastname: Wei
authors.forename: Michael F
authors.initials: MF
authors.lastname: Holick
mesh_terms: D002118:Calcium / Q000378:metabolism; D016022:Case-Control Studies; D002986:Clinical Trials as Topic; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000378:metabolism / Q000517:prevention & control*; D005260:Female; D006801:Humans; D015994:Incidence; D016239:MEDLINE; D008297:Male; D014807:Vitamin D / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*
chemical_list: D014807:Vitamin D; D002118:Calcium