title: Plasma phytanic acid concentration and risk of prostate cancer: results from the European Prospective Investigation into Cancer and Nutrition.
abstract: BACKGROUND
  Phytanic acid, a fatty acid predominantly obtained from foods high in ruminant fat, may have a biological role in the up-regulation of the protein alpha-methylacyl-coenzyme A racemase, which is overexpressed in prostate cancer tissue.
  
  
  OBJECTIVE
  This study aimed to examine the association between plasma concentrations of phytanic acid and subsequent risk of prostate cancer.
  
  
  METHODS
  Within the European Prospective Investigation into Cancer and Nutrition cohort, 566 incident prostate cancer cases from Germany, Greece, Italy, the Netherlands, Spain, and the United Kingdom were individually matched to 566 controls by study center, age at recruitment, and time of day and duration of fasting at blood collection. Phytanic acid concentrations were measured by using a gas chromatography-mass spectrometry assay.
  
  
  RESULTS
  In controls, plasma phytanic acid concentration was strongly correlated with dairy fat intake (r = 0.49, P < 0.0001), varied significantly by country (P for heterogeneity < 0.0001), and decreased with age (P for trend = 0.02) and duration of fasting at blood collection (P for trend = 0.002). There was no significant association of phytanic acid with prostate cancer risk overall (odds ratio for a doubling in concentration: 1.05; 95% CI: 0.91, 1.21; P for trend = 0.53) or by stage or grade of disease. However, in men who had fasted (>3 h) at blood collection, the odds ratio for prostate cancer was 1.27 (95% CI: 1.01, 1.60; P for trend = 0.04).
  
  
  CONCLUSIONS
  Plasma phytanic acid concentration is significantly associated with intake of dairy fat but not with overall risk of prostate cancer in this European population.
authors.affiliation: Nuffield Department of Clinical Medicine, University of Oxford, United Kingdom. alison.price@ceu.ox.ac.uk <alison.price@ceu.ox.ac.uk>
authors.forename: Alison J
authors.initials: AJ
authors.lastname: Price
authors.forename: Naomi E
authors.initials: NE
authors.lastname: Allen
authors.forename: Paul N
authors.initials: PN
authors.lastname: Appleby
authors.forename: Francesca L
authors.initials: FL
authors.lastname: Crowe
authors.forename: Mazda
authors.initials: M
authors.lastname: Jenab
authors.forename: Sabina
authors.initials: S
authors.lastname: Rinaldi
authors.forename: Nadia
authors.initials: N
authors.lastname: Slimani
authors.forename: Rudolf
authors.initials: R
authors.lastname: Kaaks
authors.forename: Sabine
authors.initials: S
authors.lastname: Rohrmann
authors.forename: Heiner
authors.initials: H
authors.lastname: Boeing
authors.forename: Tobias
authors.initials: T
authors.lastname: Pischon
authors.forename: Vassiliki
authors.initials: V
authors.lastname: Benetou
authors.forename: Androniki
authors.initials: A
authors.lastname: Naska
authors.forename: Antonia
authors.initials: A
authors.lastname: Trichopoulou
authors.forename: Domenico
authors.initials: D
authors.lastname: Palli
authors.forename: Sabina
authors.initials: S
authors.lastname: Sieri
authors.forename: Rosario
authors.initials: R
authors.lastname: Tumino
authors.forename: Paolo
authors.initials: P
authors.lastname: Vineis
authors.forename: H Bas
authors.initials: HB
authors.lastname: Bueno-de-Mesquita
authors.forename: Ignacio
authors.initials: I
authors.lastname: Donate
authors.forename: Carlos A
authors.initials: CA
authors.lastname: González
authors.forename: Maria-José
authors.initials: MJ
authors.lastname: Sánchez
authors.forename: Maria-Dolores
authors.initials: MD
authors.lastname: Chirlaque
authors.forename: Eva
authors.initials: E
authors.lastname: Ardanaz
authors.forename: Nerea
authors.initials: N
authors.lastname: Larrañaga
authors.forename: Kay-Tee
authors.initials: KT
authors.lastname: Khaw
authors.forename: Sheila
authors.initials: S
authors.lastname: Rodwell
authors.forename: Valentina
authors.initials: V
authors.lastname: Gallo
authors.forename: Dominique S
authors.initials: DS
authors.lastname: Michaud
authors.forename: Elio
authors.initials: E
authors.lastname: Riboli
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Key
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D005060:Europe / Q000453:epidemiology; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D010831:Phytanic Acid / Q000097:blood*; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000097:blood* / Q000453:epidemiology / Q000473:pathology
chemical_list: D010831:Phytanic Acid