title: Prognostic effects of 25-hydroxyvitamin D levels in early breast cancer.
abstract: OBJECTIVE
  Vitamin D has been linked to breast cancer risk, but prognostic effects are unknown. Such effects are biologically plausible given the presence of vitamin D receptors in breast cancer cells, which act as nuclear transcription factors to regulate gene activity.
  
  
  METHODS
  The study was conducted in a prospective inception cohort of 512 women with early breast cancer diagnosed 1989 to 1996. Vitamin D levels were measured in stored blood. Clinical, pathologic, and dietary data were accessed to examine prognostic effects of vitamin D.
  
  
  RESULTS
  Mean age was 50.4 years, mean vitamin D was 58.1 +/- 23.4 nmol/L. Vitamin D levels were deficient (< 50 nmol/L) in 37.5% of patients, insufficient (50 to 72 nmol/L) in 38.5% of patients, and sufficient (> 72 nmol/L) in 24.0% of patients. There was little variation in mean vitamin D levels between summer and winter months. Mean follow-up was 11.6 years; 116 women had distant recurrences, and 106 women died. Women with deficient vitamin D levels had an increased risk of distant recurrence (hazard ratio [HR] = 1.94; 95% CI, 1.16 to 3.25) and death (HR = 1.73; 95% CI, 1.05 to 2.86) compared with those with sufficient levels. The association remained after individual adjustment for key tumor and treatment related factors but was attenuated in multivariate analyses (HR = 1.71; 95% CI, 1.02 to 2.86 for distant recurrence; HR = 1.60; 95% CI, 0.96 to 2.64 for death).
  
  
  CONCLUSIONS
  Vitamin D deficiency may be associated with poor outcomes in breast cancer.
authors.affiliation: Mount Sinai Hospital, 1284-600 University Ave, Toronto, Ontario M5G 1X4, Canada. pgoodwin@mtsinai.on.ca
authors.forename: Pamela J
authors.initials: PJ
authors.lastname: Goodwin
authors.forename: Marguerite
authors.initials: M
authors.lastname: Ennis
authors.forename: Kathleen I
authors.initials: KI
authors.lastname: Pritchard
authors.forename: Jarley
authors.initials: J
authors.lastname: Koo
authors.forename: Nicky
authors.initials: N
authors.lastname: Hood
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000097:blood* / Q000378:metabolism / Q000473:pathology*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008875:Middle Aged; D015999:Multivariate Analysis; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D011795:Surveys and Questionnaires; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000150:complications* / Q000378:metabolism*
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D