title: Plasma phospholipids fatty acids, dietary fatty acids, and breast cancer risk.
abstract: This study prospectively investigates associations between fatty acids assessed in plasma phospholipids (PPL) and diet, and breast cancer risk, including subgroups defined by hormone receptor status.
  
  
  
  We performed a case-cohort analysis within the Melbourne Collaborative Cohort Study using a random sample of 2,021 women and 470 breast cancer cases. At baseline, fatty acids were assessed in PPL and estimated from diet using a 121-item food frequency questionnaire. Hazard ratios (HR) and 95 % confidence intervals (CI) were estimated using Cox regression.
  
  
  
  Breast cancer risk was positively associated with %PPL saturated fatty acids (SFA); HRQ5vsQ1 = 1.64 (95 % CI 1.17-2.30); p trend = 0.004. Positive associations were found for ER+ or PR+ tumors for %PPL SFA and palmitic acid and for ER-/PR- tumors for %PPL n-6 polyunsaturated fatty acid (PUFA), TFA, TFA 16:1, and TFA 18:1n-7 (all p homogeneity <0.05). Breast cancer risk was inversely associated with dietary docosapentaenoic acid (DPA); HRQ5vsQ1 = 0.57 (95 % CI 0.40-0.82); p trend = 0.001 [with similar inverse associations observed for dietary docosahexaenoic (DHA) and eicosapentaenoic acid (EPA)] and positively associated with dietary n-6:n-3 PUFA. Inverse associations for ER-/PR- tumors were found for dietary dihomo-γ-linolenic acid (DGLA) for older women (p homogeneity = 0.04).
  
  
  
  Breast cancer risk was positively associated with %PPL SFA and the ratio of dietary n-6 to n-3 PUFA and inversely associated with dietary long-chain n-3 PUFA intake. Some associations between fatty acids and breast cancer varied by age and tumor phenotype defined by hormone receptor status. Increased intake of fish and other foods rich in long-chain n-3 PUFAs and reduced n-6 PUFA intake might reduce breast cancer risk.
authors.affiliation: Cancer Epidemiology Centre, Cancer Council Victoria, 615 St Kilda Road, Melbourne, VIC, 3004, Australia. julie.bassett@cancervic.org.au.
authors.forename: Julie K
authors.initials: JK
authors.lastname: Bassett
authors.affiliation: Cancer Epidemiology Centre, Cancer Council Victoria, 615 St Kilda Road, Melbourne, VIC, 3004, Australia.
authors.forename: Allison M
authors.initials: AM
authors.lastname: Hodge
authors.affiliation: Cancer Epidemiology Centre, Cancer Council Victoria, 615 St Kilda Road, Melbourne, VIC, 3004, Australia.|Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, VIC, 3010, Australia.
authors.forename: Dallas R
authors.initials: DR
authors.lastname: English
authors.affiliation: Cancer Epidemiology Centre, Cancer Council Victoria, 615 St Kilda Road, Melbourne, VIC, 3004, Australia.|Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, VIC, 3010, Australia.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: MacInnis
authors.affiliation: Cancer Epidemiology Centre, Cancer Council Victoria, 615 St Kilda Road, Melbourne, VIC, 3004, Australia.|Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, VIC, 3010, Australia.|Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, VIC, 3004, Australia.
authors.forename: Graham G
authors.initials: GG
authors.lastname: Giles
mesh_terms: D015126:8,11,14-Eicosatrienoic Acid; D000230:Adenocarcinoma / Q000097:blood / Q000453:epidemiology* / Q000378:metabolism; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D001943:Breast Neoplasms / Q000097:blood / Q000453:epidemiology* / Q000378:metabolism; D016022:Case-Control Studies; D004032:Diet / Q000706:statistics & numerical data*; D004041:Dietary Fats; D004042:Dietary Fats, Unsaturated; D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid; D005227:Fatty Acids; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated; D005260:Female; D005399:Fishes; D006801:Humans; D008875:Middle Aged; D010743:Phospholipids / Q000097:blood*; D016016:Proportional Hazards Models; D011446:Prospective Studies; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D012306:Risk
chemical_list: D004041:Dietary Fats; D004042:Dietary Fats, Unsaturated; D005227:Fatty Acids; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated; D010743:Phospholipids; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid; D015126:8,11,14-Eicosatrienoic Acid; C026219:docosapentaenoic acid
keywords: Breast cancer; Cohort study; Fatty acids; Melbourne Collaborative Cohort Study