Schatzkin Arthur, Mouw Traci, Park Yikyung, Subar Amy F, Kipnis Victor, Hollenbeck Albert, Leitzmann Michael F, Thompson Frances E
Division of Cancer Epidemiology, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, USA.
Am J Clin Nutr. 2007 May;85(5):1353-60. doi: 10.1093/ajcn/85.5.1353.
Whether the intake of dietary fiber can protect against colorectal cancer is a long-standing question of considerable public health import, but the epidemiologic evidence has been inconsistent.
The objective was to investigate the relation between dietary fiber and whole-grain food intakes and invasive colorectal cancer in the prospective National Institutes of Health-AARP Diet and Health Study.
The analytic cohort consisted of 291 988 men and 197 623 women aged 50-71 y. Diet was assessed with a self-administered food-frequency questionnaire at baseline in 1995-1996; 2974 incident colorectal cancer cases were identified during 5 y of follow-up. The Cox proportional hazards model was used to estimate the relative risks (RRs) and 95% CIs.
Total dietary fiber intake was not associated with colorectal cancer. The multivariate RR for the highest compared with the lowest intake quintile (RR(Q5-Q1)) was 0.99 (95% CI: 0.85, 1.15; P for trend = 0.96). In analyses of fiber from different food sources, only fiber from grains was associated with a lower risk of colorectal cancer (multivariate RR(Q5-Q1): 0.86; 95% CI: 0.76, 0.98; P for trend = 0.01). Whole-grain intake was inversely associated with colorectal cancer risk: the multivariate RR(Q5-Q1) was 0.79 (95% CI: 0.70, 0.89) for the whole cohort (P for trend < 0.001). The association with whole grain was stronger for rectal than for colon cancer.
In this large prospective cohort study, total dietary fiber intake was not associated with colorectal cancer risk, whereas whole-grain consumption was associated with a modest reduced risk.
膳食纤维的摄入是否能预防结直肠癌是一个长期存在且具有重要公共卫生意义的问题，但流行病学证据并不一致。
在前瞻性的美国国立卫生研究院-美国退休人员协会饮食与健康研究中，调查膳食纤维和全谷物食物摄入量与浸润性结直肠癌之间的关系。
分析队列包括291988名年龄在50至71岁之间的男性和197623名女性。1995 - 1996年基线时通过自行填写的食物频率问卷评估饮食情况；在5年随访期间确定了2974例结直肠癌新发病例。使用Cox比例风险模型估计相对风险（RRs）和95%可信区间（CIs）。
总膳食纤维摄入量与结直肠癌无关。最高摄入量五分位数与最低摄入量五分位数相比的多变量RR（RR(Q5 - Q1)）为0.99（95% CI：0.85，1.15；趋势P值 = 0.96）。在对不同食物来源的纤维进行分析时，仅谷物纤维与较低的结直肠癌风险相关（多变量RR(Q5 - Q1)：0.86；95% CI：0.76，0.98；趋势P值 = 0.01）。全谷物摄入量与结直肠癌风险呈负相关：整个队列的多变量RR(Q5 - Q1)为0.79（95% CI：0.70，0.89）（趋势P值 < 0.001）。全谷物与直肠癌的关联比结肠癌更强。
在这项大型前瞻性队列研究中，总膳食纤维摄入量与结直肠癌风险无关，而全谷物消费与风险适度降低相关。
