title: Plasma phospholipid fatty acids, dietary fatty acids and prostate cancer risk.
abstract: Animal and experimental studies have demonstrated that long-chain n-3 fatty acids inhibit the development of prostate cancer, whereas n-6 fatty acids might promote it. We performed a case-cohort analysis within the Melbourne Collaborative Cohort Study using a random sample of 1,717 men and 464 prostate cancer cases to investigate associations between fatty acids assessed in plasma phospholipids (PPLs) or diet (estimated using a 121-item food frequency questionnaire) and prostate cancer risk. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox regression. Prostate cancer risk was positively associated with %PPL saturated fatty acids (SFAs); HR [95% CI] = 1.51 [1.06, 2.16] (Q5 vs. Q1, fifth vs. first quintile); p-trend = 0.003. HRs (Q5 to Q2 vs. Q1) were significantly elevated for %PPL palmitic acid. %PPL oleic acid was inversely associated with risk, HR = 0.62 [0.43, 0.91] (Q5 vs. Q1); p-trend = 0.04. No statistically significant linear trends were observed for dietary intakes. The HRs were elevated for moderate intakes of linoleic acid (Q2 and Q3 vs. Q1, 1.58 [1.10, 2.28] and 1.70 [1.18, 2.46], respectively), but the increase was not significant for higher intakes (Q4 and Q5). No association varied significantly by tumour aggressiveness (all p-homogeneity > 0.1). Prostate cancer risk was positively associated with %PPL SFA, largely attributable to palmitic acid and inversely associated with %PPL monounsaturated fatty acids, largely attributable to oleic acid. Higher risks were also observed for dietary n-6 polyunsaturated fats, primarily linoleic acid.
authors.affiliation: Cancer Epidemiology Centre, Cancer Council Victoria, Carlton, VIC, Australia. julie.bassett@cancervic.org.au
authors.forename: Julie K
authors.initials: JK
authors.lastname: Bassett
authors.forename: Gianluca
authors.initials: G
authors.lastname: Severi
authors.forename: Allison M
authors.initials: AM
authors.lastname: Hodge
authors.forename: Robert J
authors.initials: RJ
authors.lastname: MacInnis
authors.forename: Robert A
authors.initials: RA
authors.lastname: Gibson
authors.forename: John L
authors.initials: JL
authors.lastname: Hopper
authors.forename: Dallas R
authors.initials: DR
authors.lastname: English
authors.forename: Graham G
authors.initials: GG
authors.lastname: Giles
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D015331:Cohort Studies; D004032:Diet; D004041:Dietary Fats / Q000008:administration & dosage*; D005227:Fatty Acids / Q000097:blood*; D005229:Fatty Acids, Monounsaturated / Q000008:administration & dosage; D043371:Fatty Acids, Omega-6 / Q000008:administration & dosage; D005260:Female; D006801:Humans; D019787:Linoleic Acid / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D019301:Oleic Acid / Q000008:administration & dosage; D019308:Palmitic Acid / Q000008:administration & dosage; D010743:Phospholipids / Q000097:blood*; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000097:blood*; D012307:Risk Factors; D011795:Surveys and Questionnaires
chemical_list: D004041:Dietary Fats; D005227:Fatty Acids; D005229:Fatty Acids, Monounsaturated; D043371:Fatty Acids, Omega-6; D010743:Phospholipids; D019301:Oleic Acid; D019308:Palmitic Acid; D019787:Linoleic Acid
keywords: cohort study; fatty acids; prostate cancer