title: Intake of omega-3 and omega-6 fatty acids and risk of ovarian cancer.
abstract: OBJECTIVE
  Limited experimental evidence suggests that omega-3 polyunsaturated (n-3) fatty acids inhibit the proliferation of ovarian cancer cells in vitro, whereas omega-6 polyunsaturated (n-6) fatty acids have been shown to promote carcinogenesis, but epidemiological studies to date have been inconclusive. Our aim was to evaluate the role of polyunsaturated fatty acids in ovarian carcinogenesis.
  
  
  METHODS
  Participants in the Australian Ovarian Cancer Study (1,366 cases and 1,414 population controls) self-completed risk factor and food frequency questionnaires. Logistic regression models were used to calculate adjusted odds ratio (OR) and 95 % confidence intervals (CI).
  
  
  RESULTS
  We found no association between intake of total n-3 fatty acids from foods, or the individual n-3 fatty acids-alpha-linolenic, eicosapentaenoic, docosapentaenoic, docosahexaenoic acids-and ovarian cancer risk. High intake of total n-6 fatty acids was inversely associated with risk (OR for highest vs. lowest category 0.78, 95 % CI 0.60-1.00, p-trend 0.04); however, the association was restricted to n-6 fatty acids from avocado, vegetables, and nuts. Neither higher intake of the individual n-6 fatty acids nor the ratio of n-3 to n-6 fatty acids was associated with ovarian cancer risk. We found no evidence that risk varied by supplement use.
  
  
  CONCLUSIONS
  Our data provide no evidence of a protective role for n-3 fatty acids in ovarian carcinogenesis. The benefit, if any, of higher intake of n-6 fatty acids is due to general properties of the food sources, rather than due to the n-6 fatty acids per se.
authors.affiliation: Genetics and Population Health Division, Queensland Institute of Medical Research, 300 Herston Rd, Herston, Brisbane, QLD 4006, Australia.
authors.forename: T I
authors.initials: TI
authors.lastname: Ibiebele
authors.forename: C M
authors.initials: CM
authors.lastname: Nagle
authors.forename: C J
authors.initials: CJ
authors.lastname: Bain
authors.forename: P M
authors.initials: PM
authors.lastname: Webb
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001315:Australia / Q000453:epidemiology; D016022:Case-Control Studies; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage* / Q000009:adverse effects; D043371:Fatty Acids, Omega-6 / Q000008:administration & dosage* / Q000009:adverse effects; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D008875:Middle Aged; D010051:Ovarian Neoplasms / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D012307:Risk Factors; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6