Assessing the effect of fatty acids on prostate carcinogenesis in humans: does self-reported dietary intake rank prostatic exposure correctly?
BACKGROUND
Dietary fatty acids may influence prostate carcinogenesis. Although the standard for assessing dietary effects in humans is the semiquantitative food-frequency questionnaire, the extent to which self-reported intake correctly ranks prostatic exposure is unknown.


OBJECTIVE
The objective was to examine the correlation between reported intakes of different fatty acids and their concentrations in prostate tissue.


METHODS
This was a cross-sectional study of 52 men undergoing surgical resection of the prostate gland. Usual dietary intake of saturated, total unsaturated, oleic, and linoleic fatty acids over the previous year was estimated with use of a 122-item version of the Health Habits and History Questionnaire. Concentrations in prostate tissue were measured directly by use of gas chromatography in healthy tissue collected at the time of surgery and were expressed as a percentage of total fatty acids. Correlations with 4 measures of dietary intake [g/d, g/d adjusted for total daily energy intake, % of total fat (as g/d), and % of total energy] were evaluated by Spearman's rank-order correlation coefficients.


RESULTS
Linoleic acid concentrations in prostate tissue were significantly correlated with dietary intake expressed as g/d adjusted for total energy [r = 0.29 (95% CI: 0.03, 0.49), P = 0.04], % of total fat [r = 0.36 (0.14, 0.550), P = 0.008], and % of total energy [r = 0.28 (0.04, 0.49), P = 0.042], but not as g/d. Although mean concentrations of saturated, total unsaturated, and oleic fatty acids in prostate tissue resembled mean intakes for the group, prostatic concentrations did not correlate with individual intakes.


CONCLUSIONS
Self-reported intake of fatty acids is a satisfactory marker of prostatic exposure at the group level, but, with the exception of linoleic acid, does not correctly rank individuals with respect to intensity of exposure.
Midwest Center for Health Services and Policy Research, Department of Veterans Affairs, Edward Hines, Jr. Hospital, Hines, IL 60141, USA. vfreeman@wpo.it.luc.edu
V L
VL
Freeman
M
M
Meydani
S
S
Yong
J
J
Pyle
R
R
Durazo-Arvizu
Y
Y
Liao
R C
RC
Flanigan
W B
WB
Waters
D000368:Aged; D015415:Biomarkers / Q000032:analysis; D002849:Chromatography, Gas; D003430:Cross-Sectional Studies; D004032:Diet; D005227:Fatty Acids / Q000008:administration & dosage* / Q000032:analysis*; D006801:Humans; D019787:Linoleic Acid / Q000378:metabolism; D008297:Male; D011467:Prostate / Q000378:metabolism*; D011471:Prostatic Neoplasms / Q000209:etiology*; D012307:Risk Factors; D012650:Self Disclosure; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires
D015415:Biomarkers; D005227:Fatty Acids; D019787:Linoleic Acid