title: Do vitamin A serum levels moderate outcome or the protective effect of vitamin D on outcome from malignant melanoma?
abstract: OBJECTIVE
  Low serum vitamin D levels (25-OH-vit D2/3) are reported to be associated with thicker melanomas and poorer outcome. Vitamin A metabolites and vitamin D bind to the same heterodimeric receptor. We report a study testing the hypothesis that high vitamin A levels may reduce the protective effect of vitamin D on outcome.
  
  
  METHODS
  Serum vitamin A levels were measured in 795 melanoma cases and assessed for association with Breslow thickness, overall (OS) and melanoma-specific survival (MSS), and modification of the effect of vitamin D levels on survival.
  
  
  RESULTS
  Higher vitamin A levels (≥ 2.2 μmol/l) conferred a non-significant increased risk of melanoma-specific death (adjusted HR = 1.11, 95%CI(0.74-1.67), p = 0.60) but not for death overall (adjusted HR = 0.95, 95%CI(0.65-1.39), p = 0.79). There was reduction in the protective effect of vitamin D on OS in patients with high vitamin A levels (≥ 2.2 μmol/l)(HR = 0.99, 95%CI(0.72-1.36),p = 0.93) compared to patients with low levels (<2.2 μmol)(HR = 0.77, 95%CI(0.64-0.93),p = 0.007), although the difference was not statistically significant (p = 0.26).
  
  
  CONCLUSIONS
  High vitamin A levels may reduce the protective effect of vitamin D. As sub-optimal levels of vitamin D are common in temperate climates, and are usually managed by dietary supplementation, we suggest vitamin D3 supplementation alone might be preferable for melanoma patients than preparations containing vitamin D and A.
authors.affiliation: Section of Epidemiology & Biostatistics, Leeds Institute of Cancer Studies and Pathology, University of Leeds, Cancer Genetics Building, St. James's University Hospital, Leeds LS9 7TF, United Kingdom. Electronic address: s.field@leeds.ac.uk.
authors.forename: Sinead
authors.initials: S
authors.lastname: Field
authors.forename: Faye
authors.initials: F
authors.lastname: Elliott
authors.forename: Juliette
authors.initials: J
authors.lastname: Randerson-Moor
authors.forename: Kairen
authors.initials: K
authors.lastname: Kukalizch
authors.forename: Jennifer H
authors.initials: JH
authors.lastname: Barrett
authors.forename: D Timothy
authors.initials: DT
authors.lastname: Bishop
authors.forename: Julia A
authors.initials: JA
authors.lastname: Newton-Bishop
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008545:Melanoma / Q000097:blood* / Q000150:complications / Q000188:drug therapy; D008875:Middle Aged; D014801:Vitamin A / Q000008:administration & dosage / Q000009:adverse effects / Q000097:blood*; D014807:Vitamin D / Q000008:administration & dosage / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood / Q000150:complications
chemical_list: D014801:Vitamin A; D014807:Vitamin D
keywords: Dietary supplements; Melanoma; Survival; Vitamin A; Vitamin D