title: Genetic variability in prostaglandin synthesis, fish intake and risk of colorectal polyps.
abstract: Dietary polyunsaturated fatty acids (PUFAs) can be converted to prostaglandins and leukotrienes. Metabolism of omega-6 (n-6) PUFAs results in the production of pro-inflammatory mediators whereas downstream products of omega-3 (n-3) PUFAs have lower inflammatory activity. Elevated n-3 PUFA intake from dietary fish may be associated with lower risk of colorectal neoplasia among those with genetic variants resulting in higher levels of pro-inflammatory mediators. We investigated interactions between dietary fish intake and polymorphisms in cyclooxygenase (COX)-1, COX-2, ALOX5 and PGIS in a case-control study of adenomas (N = 522), hyperplastic polyps (N = 194) and polyp-free controls (N = 626). Polyp risk did not differ by fish intake. A suggested interaction with fish intake was observed for COX-1 P17L. Among those who were homozygous wild type, increasing fish intake was associated with a modestly reduced risk of adenoma, whereas among those with at least one variant allele, the reverse trend was observed (p-interaction = 0.08). The interaction was statistically significant when non-steroidal anti-inflammatory drug (NSAID) use was also taken into account: among those with COX-1 17PP genotypes, high fish intake and regular NSAID use was associated with a decreased risk compared with low fish intake and low NSAID use (odds ratio = 0.60, 95% confidence interval 0.33-1.09). The opposite association was observed among those with COX-1 17PL or LL genotypes (p-interaction = 0.04). Our results suggest that the effects of dietary n-3 PUFA intake and NSAID use may differ by genetic variation in COX-1.
authors.affiliation: Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Poole
authors.forename: Jeannette
authors.initials: J
authors.lastname: Bigler
authors.forename: John
authors.initials: J
authors.lastname: Whitton
authors.forename: Justin G
authors.initials: JG
authors.lastname: Sibert
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Kulmacz
authors.forename: John D
authors.initials: JD
authors.lastname: Potter
authors.forename: Cornelia M
authors.initials: CM
authors.lastname: Ulrich
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D016022:Case-Control Studies; D003111:Colonic Polyps / Q000235:genetics*; D004032:Diet; D015525:Fatty Acids, Omega-3 / Q000378:metabolism; D005260:Female; D005399:Fishes; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation; D006801:Humans; D008297:Male; D008875:Middle Aged; D011453:Prostaglandins / Q000096:biosynthesis / Q000235:genetics*; D012307:Risk Factors
chemical_list: D015525:Fatty Acids, Omega-3; D011453:Prostaglandins