title: Vitamin D deficiency at melanoma diagnosis is associated with higher Breslow thickness.
abstract: BACKGROUND
  Epidemiological evidence shows that people with thicker, or higher stage, melanomas have lower vitamin D status compared to those with thinner tumours. Evidence from experimental studies is inconsistent, but some suggest that administration of vitamin D metabolites can decrease tumour aggressiveness.
  
  
  OBJECTIVE
  Determine the relationship between vitamin D status at diagnosis and melanoma thickness (as an indicator of prognosis), in a subtropical setting with high melanoma incidence.
  
  
  METHODS
  We recruited 100 melanoma patients in Brisbane, Australia within days of their diagnosis. Data on factors previously associated with melanoma risk or prognosis were collected by questionnaire and physical examination. Serum for 25-hydroxyvitamin D3 [25(OH)D] levels was collected prior to wider excision biopsy; histological indicators of prognosis were obtained from pathology reports. We used multivariable logistic regression models to analyse the association between Breslow thickness (≥0.75 mm compared to <0.75 mm), Clark level (2-5 compared to 1) and presence of mitoses, and vitamin D status.
  
  
  RESULTS
  Serum 25(OH)D <50 nmol/L (versus ≥50 nmol/L) was associated with a nearly four-fold increase in risk of having a thicker tumour (Adjusted OR = 3.82, 95% CI: 1.03, 14.14; p = 0.04, adjusted for age, sex, skin phototype, body mass index and season at diagnosis). There was no significant association with Clark level or presence of mitosis. Serum 25(OH)D levels in the highest quartile (≥69.8 nmol/L) were not associated with a more favourable prognosis.
  
  
  CONCLUSIONS
  Vitamin D deficiency at the time of melanoma diagnosis is associated with thicker tumours that are likely to have a poorer prognosis. Ensuring vitamin D levels of 50 nmol/L or higher in this population could potentially result in 18% of melanomas having Breslow thickness of <0.75 mm rather than ≥0.75 mm.
authors.affiliation: AusSun Research Laboratory, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia.
authors.forename: Candy
authors.initials: C
authors.lastname: Wyatt
authors.affiliation: National Centre for Epidemiology and Population Health, The Australian National University, Canberra, Australia; Telethon Kids Institute, University of Western Australia, Perth, Australia.
authors.forename: Robyn M
authors.initials: RM
authors.lastname: Lucas
authors.affiliation: Faculty of Public Health, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: Cameron
authors.initials: C
authors.lastname: Hurst
authors.affiliation: AusSun Research Laboratory, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Kimlin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002112:Calcifediol / Q000097:blood; D004198:Disease Susceptibility; D005260:Female; D006801:Humans; D008297:Male; D008545:Melanoma / Q000097:blood / Q000209:etiology / Q000473:pathology*; D008875:Middle Aged; D012720:Severity of Illness Index; D012878:Skin Neoplasms / Q000097:blood / Q000209:etiology / Q000473:pathology*; D047368:Tumor Burden; D014808:Vitamin D Deficiency / Q000097:blood / Q000150:complications*
chemical_list: D002112:Calcifediol