Am J Clin Nutr 2011 Jan 20;93(1):101-7. Epub 2010 Oct 20.
Shanghai Cancer Institute, Shanghai, China.
Background: Mixed results have been reported in recent epidemiologic studies in Western populations that have investigated the hypothesis that high glycemic load may increase the risk of colorectal cancer. This association has not been prospectively evaluated in other populations.
Objective: We examined the association of overall glycemic index and glycemic load with colorectal cancer risk in a prospective cohort of Chinese women.
Design: A total of 73,061 women aged 40-70 y and free of cancer at enrollment were included in this analysis. Usual dietary intake was assessed at baseline (1997-2000) and reassessed during the first follow-up (2000-2002) through in-person interviews by using a validated food-frequency questionnaire.
Results: During an average follow-up of 9.1 y, 475 incident colorectal cancer cases were identified. Glycemic load was not associated with colorectal cancer risk (P for trend = 0.84). The multivariable hazard ratio for the highest compared with the lowest quintile of glycemic load was 0.94 (95% CI: 0.71, 1.24). Similar results were also observed for associations with dietary glycemic index and total carbohydrate intake, and results did not vary by excluding individuals with a history of diabetes from the analysis.
Conclusion: This prospective study, conducted in a population with a high intake of carbohydrates, provides no evidence that a high-glycemic index diet or high glycemic load is associated with an increased risk of colorectal cancer.