Dietary carbohydrate, glycemic index, and glycemic load in relation to risk of colorectal cancer in women

Diets with a high glycemic index and glycemic load have been hypothesized to be implicated in the etiology of colorectal cancer owing to their potential to increase postprandial glucose and insulin levels. Prospective data on glycemic index and glycemic load in relation to colorectal cancer risk are limited and inconsistent. Therefore, the authors prospectively investigated the associations of dietary carbohydrate, glycemic index, and glycemic load with the incidence of colorectal cancer among 61,433 Swedish women who were free of cancer in 1987-1990 and completed a 67-item food frequency questionnaire. During follow-up through June 2005, 870 incident cases of colorectal adenocarcinoma were diagnosed. Carbohydrate intake, glycemic index, and glycemic load were not associated with risk of colorectal cancer, colon cancer, or rectal cancer. The multivariate hazard ratios for colorectal cancer comparing the highest with the lowest quintile were 1.10 (95% confidence interval: 0.85, 1.44) for carbohydrate intake, 1.00 (95% confidence interval: 0.75, 1.33) for glycemic index, and 1.06 (95% confidence interval: 0.81, 1.39) for glycemic load. Results did not vary by body mass index. The findings from this prospective study do not support the hypothesis that a high carbohydrate intake, a high glycemic index, and a high glycemic load increase the risk of colorectal cancer.