title: Associations of circulating and dietary vitamin D with prostate cancer risk: a systematic review and dose-response meta-analysis.
abstract: OBJECTIVE
  We systematically reviewed and meta-analyzed literature examining associations of vitamin D (dietary intake, circulating 25-hydroxy-vitamin-D (25(OH)D), and 1,25-dihydroxy-vitamin-D (1,25(OH)(2)D) concentrations) with prostate cancer.
  
  
  METHODS
  We searched over 24,000 papers from seven electronic databases (to October 2010) for exposures related to vitamin D. We conducted dose-response random-effects meta-analyses pooling the log odds ratio (OR) and 95% confidence intervals (CI) per change in natural units of each exposure. The I(2) statistic quantified between-study variation due to heterogeneity.
  
  
  RESULTS
  Twenty-five papers were included. In prospective studies, the OR per 1,000 IU increase in dietary intake was 1.14 (6 studies; CI: 0.99, 1.31; I (2) = 0%) for total prostate cancer and 0.93 (3 studies; 0.63, 1.39; I (2) = 25%) for aggressive prostate cancer. Five case-control studies examined dietary intake, but there was a high degree of inconsistency between studies (I (2) = 49%). The OR per 10 ng/mL increase in 25(OH)D was 1.04 (14 studies; 0.99, 1.10; I (2) = 0%) for total prostate cancer and 0.98 (6 studies; 0.84, 1.15; I (2) = 32%) for aggressive prostate cancer. The OR per 10 pg/mL increase in 1,25(OH)(2)D was 1.00 (7 studies; 0.87, 1.14; I (2) = 41%) for total prostate cancer and 0.86 (2 studies; 0.72, 1.02; I (2) = 0%) for aggressive prostate cancer.
  
  
  CONCLUSIONS
  Published literature provides little evidence to support a major role of vitamin D in preventing prostate cancer or its progression.
authors.affiliation: School of Social and Community Medicine, University of Bristol, Canynge Hall, 39 Whatley Road, Bristol BS8 2PS, UK. Becky.Gilbert@Bristol.ac.uk
authors.forename: Rebecca
authors.initials: R
authors.lastname: Gilbert
authors.forename: Richard M
authors.initials: RM
authors.lastname: Martin
authors.forename: Rebecca
authors.initials: R
authors.lastname: Beynon
authors.forename: Ross
authors.initials: R
authors.lastname: Harris
authors.forename: Jelena
authors.initials: J
authors.lastname: Savovic
authors.forename: Luisa
authors.initials: L
authors.lastname: Zuccolo
authors.forename: Geertruida E
authors.initials: GE
authors.lastname: Bekkering
authors.forename: William D
authors.initials: WD
authors.lastname: Fraser
authors.forename: Jonathan A C
authors.initials: JA
authors.lastname: Sterne
authors.forename: Chris
authors.initials: C
authors.lastname: Metcalfe
mesh_terms: D016022:Case-Control Studies; D004032:Diet; D006801:Humans; D008297:Male; D016017:Odds Ratio; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000209:etiology*; D012306:Risk; D014807:Vitamin D / Q000494:pharmacology*; D014815:Vitamins / Q000494:pharmacology
chemical_list: D014815:Vitamins; D014807:Vitamin D