Wakai Kenji, Date Chigusa, Fukui Mitsuru, Tamakoshi Koji, Watanabe Yoshiyuki, Hayakawa Norihiko, Kojima Masayo, Kawado Miyuki, Suzuki Koji, Hashimoto Shuji, Tokudome Shinkan, Ozasa Kotaro, Suzuki Sadao, Toyoshima Hideaki, Ito Yoshinori, Tamakoshi Akiko
Division of Epidemiology and Prevention, Aichi Cancer Center Research Institute, 1-1 Kanokoden, Chikusa-ku, Nagoya 464-8681, Japan.
Cancer Epidemiol Biomarkers Prev. 2007 Apr;16(4):668-75. doi: 10.1158/1055-9965.EPI-06-0664.
To examine the association of dietary fiber with the risk of colorectal cancer in a population with a high incidence of cancer and a low fiber intake, we analyzed the data from the Japan Collaborative Cohort Study. From 1988 to 1990, 43,115 men and women aged 40 to 79 years completed a questionnaire on dietary and other factors. Intake of dietary fiber was estimated using a food frequency questionnaire. Rate ratios (RR) were computed by fitting proportional hazards models. During the mean follow-up of 7.6 years, 443 colorectal cancer cases were recorded. In all participants, we found a decreasing trend in risk of colorectal cancer with increasing intake of total dietary fiber; the multivariate-adjusted RRs across quartiles were 1.00, 0.96 [95% confidence interval (95% CI), 0.72-1.27], 0.72 (0.53-0.99), and 0.73 (0.51-1.03; P(trend) = 0.028). This trend was exclusively detected for colon cancer: the corresponding RRs were 1.00, 0.90 (95% CI, 0.64-1.26), 0.56 (0.38-0.83), and 0.58 (0.38-0.88; P(trend) = 0.002). The decrease in RRs with increasing intake of dietary fiber was larger in men than in women. No material differences appeared in the strength of associations with the risk between water-soluble and insoluble dietary fiber. For food sources of fiber, bean fiber intake was somewhat inversely correlated with colorectal cancer risk. This prospective study supported potential protective effects of dietary fiber against colorectal cancer, mainly against colon cancer. The role of dietary fiber in the prevention of colorectal cancer seems to remain inconsistent, and further investigations in various populations are warranted. (
为了在癌症高发且膳食纤维摄入量低的人群中研究膳食纤维与结直肠癌风险的关联，我们分析了日本协作队列研究的数据。1988年至1990年，43115名年龄在40至79岁的男性和女性完成了一份关于饮食及其他因素的问卷。膳食纤维摄入量通过食物频率问卷进行估算。通过拟合比例风险模型计算率比（RR）。在平均7.6年的随访期间，记录了443例结直肠癌病例。在所有参与者中，我们发现随着总膳食纤维摄入量的增加，结直肠癌风险呈下降趋势；四分位数间经多变量调整后的RR分别为1.00、0.96 [95%置信区间（95%CI），0.72 - 1.27]、0.72（0.53 - 0.99）和0.73（0.51 - 1.03；P（趋势）= 0.028）。这种趋势仅在结肠癌中被检测到：相应的RR分别为1.00、0.90（95%CI，0.64 - 1.26）、0.56（0.38 - 0.83）和0.58（0.38 - 0.88；P（趋势）= 0.002）。随着膳食纤维摄入量增加，RR的下降在男性中比在女性中更大。水溶性和不溶性膳食纤维与风险的关联强度没有实质性差异。对于纤维的食物来源，豆类纤维摄入量与结直肠癌风险呈一定程度的负相关。这项前瞻性研究支持了膳食纤维对结直肠癌，主要是对结肠癌的潜在保护作用。膳食纤维在预防结直肠癌中的作用似乎仍不一致，有必要在不同人群中进行进一步研究。
