Plasma phytanic acid concentration and risk of prostate cancer: results from the European Prospective Investigation into Cancer and Nutrition.
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.
Price
Alison J
AJ
Nuffield Department of Clinical Medicine, University of Oxford, United Kingdom. alison.price@ceu.ox.ac.uk <alison.price@ceu.ox.ac.uk>
Allen
Naomi E
NE
Appleby
Paul N
PN
Crowe
Francesca L
FL
Jenab
Mazda
M
Rinaldi
Sabina
S
Slimani
Nadia
N
Kaaks
Rudolf
R
Rohrmann
Sabine
S
Boeing
Heiner
H
Pischon
Tobias
T
Benetou
Vassiliki
V
Naska
Androniki
A
Trichopoulou
Antonia
A
Palli
Domenico
D
Sieri
Sabina
S
Tumino
Rosario
R
Vineis
Paolo
P
Bueno-de-Mesquita
H Bas
HB
Donate
Ignacio
I
González
Carlos A
CA
Sánchez
Maria-José
MJ
Chirlaque
Maria-Dolores
MD
Ardanaz
Eva
E
Larrañaga
Nerea
N
Khaw
Kay-Tee
KT
Rodwell
Sheila
S
Gallo
Valentina
V
Michaud
Dominique S
DS
Riboli
Elio
E
Key
Timothy J
TJ
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
D010831:Phytanic Acid