Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo, Japan.
Int J Cancer. 2011 Oct 1;129(7):1718-29. doi: 10.1002/ijc.25802. Epub 2011 Apr 1.
To date, epidemiologic studies investigating intake of n-3 and n-6 polyunsaturated fatty acids and risk of colorectal cancer are limited, and results remain inconsistent. This is the first prospective study to show the association by subsite (proximal colon, distal colon, rectum). To clarify the role of n-3 and n-6 polyunsaturated fatty acids intake in colon carcinogenesis, we conducted a large, population-based prospective study, characterized by high fish consumption and a wide range of n-3 polyunsaturated fatty acids intakes. Subjects were followed from response to a lifestyle questionnaire in 1995-1999 through 2006. During 827,833 person-years of follow-up (average 9.3 years), we identified 1,268 new colorectal cancer cases (521 colon and 253 rectal for men; 350 colon and 144 rectal for women). Compared to the lowest quintile, the relative risk and 95% confidence interval of developing cancer among the fifth quintile of marine n-3 polyunsaturated fatty acids intake were 0.60 and 0.31-1.14, respectively (p for trend = 0.04) in the colon in women and 0.35 and 0.14-0.88 (p for trend = 0.05) and 1.82 and 0.79-4.20 (p for trend = 0.16) in the proximal and distal colon, respectively, in men. For rectal cancer, the dose response for marine n-3 polyunsaturated fatty acids s was unclear; rather, we observed U-shaped associations in men and women. We found no evidence that n-6 polyunsaturated fatty acids increases or the n-3/n-6 ratio decreases the risk of colorectal cancer. Our results suggest that intake of marine n-3 polyunsaturated fatty acids may be inversely related to the risk of cancer in the proximal site of the large bowel.
迄今为止，有关 n-3 和 n-6 多不饱和脂肪酸摄入与结直肠癌风险的流行病学研究有限，结果仍不一致。这是第一项通过亚部位（近端结肠、远端结肠、直肠）显示相关性的前瞻性研究。为了阐明 n-3 和 n-6 多不饱和脂肪酸摄入在结肠癌发生中的作用，我们进行了一项大型的、基于人群的前瞻性研究，其特点是鱼类摄入量高，n-3 多不饱和脂肪酸摄入量范围广泛。研究对象从 1995-1999 年对生活方式问卷的回答开始，一直随访到 2006 年。在 827833 人年的随访期间（平均随访 9.3 年），我们共发现 1268 例新发结直肠癌病例（男性 521 例结肠和 253 例直肠；女性 350 例结肠和 144 例直肠）。与最低五分位组相比，女性中五分位组海洋 n-3 多不饱和脂肪酸摄入量最高者发生癌症的相对风险和 95%置信区间分别为 0.60 和 0.31-1.14（趋势检验 p=0.04），男性中近端和远端结肠的相对风险和 95%置信区间分别为 0.35 和 0.14-0.88（趋势检验 p=0.05）和 1.82 和 0.79-4.20（趋势检验 p=0.16）。对于直肠癌，海洋 n-3 多不饱和脂肪酸的剂量反应并不明确；相反，我们在男性和女性中观察到 U 形关联。我们没有发现 n-6 多不饱和脂肪酸增加或 n-3/n-6 比值降低结直肠癌风险的证据。我们的结果表明，海洋 n-3 多不饱和脂肪酸的摄入可能与大肠近端部位癌症的风险呈负相关。
