title: A prospective study of dietary polyunsaturated fatty acids and colorectal cancer risk in Chinese women.
abstract: In animal models of colon cancer, n-3 polyunsaturated fatty acids (PUFA) have antineoplastic properties, whereas n-6 PUFAs may promote carcinogenesis. Prior epidemiologic studies have been inconsistent regarding the association of PUFAs and colorectal cancer. We prospectively evaluated the association between PUFA intake and colorectal cancer in a cohort of 73,242 Chinese women who were interviewed in person at the baseline survey for the Shanghai Women's Health Study. Dietary fatty acid consumption was derived using data collected from two food frequency questionnaires administered at baseline and 2 to 3 years later. The dietary total n-6 to n-3 PUFA ratio was strongly associated with colorectal cancer risk. Compared with women in the lowest quintile group, elevated relative risks (RR) were observed for the second [RR, 1.52; 95% confidence intervals (CI), 1.00-2.32], third (RR, 2.20; 95% CI, 1.41-3.45), fourth (RR, 1.65; 95% CI, 0.99-2.75), and fifth (RR, 1.95; 95% CI, 1.07-3.54) quintile groups. Arachidonic acid was associated with colorectal cancer risk with elevated RRs of 1.20(Q2-Q1) (95% CI, 0.87-1.64), 1.44(Q3-Q1) (95% CI, 1.05-1.98), 1.61(Q4-Q1) (95% CI, 1.17-2.23), and 1.39(Q5-Q1) (95% CI, 0.97-1.99; P(trend) = 0.03) with increasing dietary quintile. In a subset of 150 cancer cases and 150 controls, we found a statistically significant trend between an increasing n-6 to n-3 PUFA ratio and increasing production of prostaglandin E(2) (PGE(2)) as measured by urinary PGE(2) metabolites (P = 0.03). These results suggest that dietary PUFA and the ratio of n-6 to n-3 PUFA intake may be positively associated with colorectal cancer risk, and this association may be mediated in part through PGE(2) production.
authors: Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt University School of Medicine, Nashville, TN 37203-1738, USA. Harvey.j.murff@vanderbilt.edu
authors: Harvey J
authors: HJ
authors: Murff
authors: Xiao-Ou
authors: XO
authors: Shu
authors: Honglan
authors: H
authors: Li
authors: Qi
authors: Q
authors: Dai
authors: Asha
authors: A
authors: Kallianpur
authors: Gong
authors: G
authors: Yang
authors: Hui
authors: H
authors: Cai
authors: Wanqing
authors: W
authors: Wen
authors: Yu-Tang
authors: YT
authors: Gao
authors: Wei
authors: W
authors: Zheng
mesh_terms: D000328:Adult; D000368:Aged; D044466:Asian People; D002853:Chromatography, Liquid; D015179:Colorectal Neoplasms / Q000209:etiology*; D004032:Diet; D015232:Dinoprostone / Q000652:urine; D005231:Fatty Acids, Unsaturated / Q000009:adverse effects*; D005260:Female; D006801:Humans; D013058:Mass Spectrometry; D008875:Middle Aged; D012307:Risk Factors; D011795:Surveys and Questionnaires
chemical_list: D005231:Fatty Acids, Unsaturated; D015232:Dinoprostone