Channing Laboratory, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, 181 Longwood Avenue, Boston, MA 02115, USA.
Cancer Epidemiol Biomarkers Prev. 2010 Dec;19(12):3020-6. doi: 10.1158/1055-9965.EPI-10-0833. Epub 2010 Oct 5.
Circulating insulin levels have been positively associated with risk of colorectal cancer; however, it remains unclear whether a diet inducing an elevated insulin response influences colorectal cancer risk. On the basis of a novel insulin index for individual foods, we estimated insulin demand for overall diets and assessed its association with colorectal cancer in the Nurses' Health Study and Health Professionals Follow-up Study.
We followed 86,740 women and 46,146 men who were free of cancer and diabetes at baseline and identified a total of 2,481 colorectal cancer cases during up to 26 years of follow-up. Dietary insulin load was calculated as a function of food insulin index and the energy content of individual foods was reported on food frequency questionnaires. Average dietary insulin index was calculated by dividing the dietary insulin load by the total energy intake.
Dietary insulin load and dietary insulin index were not associated with risk of colorectal cancer. Comparing the highest with the lowest quintiles, the pooled multivariate relative risks of colorectal cancer were 0.91 (95% CI = 0.79-1.05) for dietary insulin load and 0.93 (95% CI = 0.81-1.08) for dietary insulin index. Body mass index and physical activity did not modify the association of dietary insulin load or index with colorectal cancer.
A diet high in foods that increase postprandial insulin levels did not increase the risk of colorectal cancer in this large prospective study.
This study is the first to investigate insulin index and load in relation to colorectal cancer.
循环胰岛素水平与结直肠癌风险呈正相关；然而，尚不清楚是否会增加胰岛素反应的饮食会影响结直肠癌的风险。基于个体食物的新胰岛素指数，我们估计了整体饮食的胰岛素需求，并在护士健康研究和健康专业人员随访研究中评估了其与结直肠癌的关系。
我们随访了 86740 名女性和 46146 名男性，这些人在基线时无癌症和糖尿病，在长达 26 年的随访中总共发现了 2481 例结直肠癌病例。饮食胰岛素负荷是根据食物胰岛素指数和个体食物的能量含量计算的，食物频率问卷报告了食物的能量含量。平均饮食胰岛素指数是通过将饮食胰岛素负荷除以总能量摄入来计算的。
饮食胰岛素负荷和饮食胰岛素指数与结直肠癌风险无关。比较最高五分位数与最低五分位数，结直肠癌的多变量相对风险为饮食胰岛素负荷 0.91（95%CI=0.79-1.05）和饮食胰岛素指数 0.93（95%CI=0.81-1.08）。体重指数和体力活动并不能改变饮食胰岛素负荷或指数与结直肠癌的关系。
在这项大型前瞻性研究中，高血糖指数食物的饮食并没有增加结直肠癌的风险。
本研究首次调查了胰岛素指数和负荷与结直肠癌的关系。
