title: Circulating concentrations of folate and vitamin B12 in relation to prostate cancer risk: results from the European Prospective Investigation into Cancer and Nutrition study.
abstract: BACKGROUND
  Determinants of one-carbon metabolism, such as folate and vitamin B(12), have been implicated in cancer development. Previous studies have not provided conclusive evidence for the importance of circulating concentrations of folate and vitamin B(12) in prostate cancer etiology. The aim of the present study was to investigate the relationship between prostate cancer risk and circulating concentrations of folate and vitamin B(12) in a large prospective cohort.
  
  
  METHODS
  We analyzed circulating concentrations of folate and vitamin B(12) in 869 cases and 1,174 controls, individually matched on center, age, and date of recruitment, nested within the European Prospective Investigation into Cancer and Nutrition cohort. Relative risks (RR) for prostate cancer were estimated using conditional logistic regression models.
  
  
  RESULTS
  Overall, no significant associations were observed for circulating concentrations of folate (P(trend) = 0.62) or vitamin B(12) (P(trend) = 0.21) with prostate cancer risk. RRs for a doubling in folate and vitamin B(12) concentrations were 1.03 [95% confidence interval (95% CI), 0.92-1.16] and 1.12 (95% CI, 0.94-1.35), respectively. In the subgroup of cases diagnosed with advanced stage prostate cancer, elevated concentrations of vitamin B(12) were associated with increased risk (RR for a doubling in concentration, 1.69; 95% CI, 1.05-2.72, P(trend) = 0.03). No other subgroup analyses resulted in a statistically significant association.
  
  
  CONCLUSIONS
  This study does not provide strong support for an association between prostate cancer risk and circulating concentrations of folate or vitamin B(12). Elevated concentrations of vitamin B(12) may be associated with an increased risk for advanced stage prostate cancer, but this association requires examination in other large prospective studies.
authors.affiliation: Department of Surgical and Perioperative Sciences, Urology and Andrology, Umeå University, 901 85 Umeå, Sweden. Mattias.Johansson@oc.umu.se
authors.forename: Mattias
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authors.lastname: Johansson
authors.forename: Paul N
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authors.lastname: Appleby
authors.forename: Naomi E
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authors.lastname: Allen
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authors.forename: Lambertus A
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authors.forename: Stein Emil
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authors.lastname: Vollset
authors.forename: Per M
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authors.lastname: Ueland
authors.forename: Maria-José
authors.initials: MJ
authors.lastname: Sánchez
authors.forename: J Ramón
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authors.lastname: Quirós
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authors.lastname: González
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authors.lastname: Larrañaga
authors.forename: María Dolores
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authors.lastname: Chirlaque
authors.forename: Eva
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authors.lastname: Ardanaz
authors.forename: Sabina
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authors.lastname: Sieri
authors.forename: Domenico
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authors.lastname: Palli
authors.forename: Paolo
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authors.lastname: Vineis
authors.forename: Rosario
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authors.lastname: Tumino
authors.forename: Jakob
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authors.lastname: Linseisen
authors.forename: Rudolf
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authors.lastname: Kaaks
authors.forename: Heiner
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authors.lastname: Boeing
authors.forename: Tobias
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authors.lastname: Pischon
authors.forename: Theodora
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authors.lastname: Psaltopoulou
authors.forename: Antonia
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authors.lastname: Trichopoulou
authors.forename: Dimitrios
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authors.lastname: Trichopoulos
authors.forename: Kay-Tee
authors.initials: KT
authors.lastname: Khaw
authors.forename: Sheila
authors.initials: S
authors.lastname: Bingham
authors.forename: Göran
authors.initials: G
authors.lastname: Hallmans
authors.forename: Elio
authors.initials: E
authors.lastname: Riboli
authors.forename: Pär
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authors.lastname: Stattin
authors.forename: Timothy J
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authors.lastname: Key
mesh_terms: D016022:Case-Control Studies; D016009:Chi-Square Distribution; D005060:Europe / Q000453:epidemiology; D005492:Folic Acid / Q000097:blood*; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000097:blood* / Q000453:epidemiology*; D012042:Registries; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014805:Vitamin B 12 / Q000097:blood*
chemical_list: D005492:Folic Acid; D014805:Vitamin B 12