Dietary fructose, carbohydrates, glycemic indices and pancreatic cancer risk: a systematic review and meta-analysis of cohort studies.

BACKGROUND Dietary carbohydrates, glycemic load and glycemic index have been hypothesized to influence pancreatic cancer risk, but epidemiological studies have been inconsistent. We conducted a systematic review and meta-analysis of prospective studies to clarify these results. METHODS PubMed and several other databases were searched for prospective studies of intake of carbohydrates, glycemic index and glycemic load and pancreatic cancer up to September 2011. Summary relative risks were estimated using a random effects model. RESULTS Ten cohort studies (13 publications) were included in the meta-analysis. The summary relative risk (RR) per 10 glycemic index units was 1.02 [95% confidence interval (CI): 0.93-1.12, I(2) = 0%], per 50 glycemic load units was 1.03 (95% CI: 0.93-1.14, I(2) = 10%), per 100 g/day of total carbohydrates was 0.97 (95% CI: 0.81-1.16, I(2) = 35%), and per 25 g/day of sucrose intake was 1.05 (95% CI: 0.85-1.23, I(2) = 53%). A positive association was observed with fructose intake, summary RR = 1.22 (95% CI: 1.08-1.37, I(2) = 0%) per 25 g/day. CONCLUSIONS This meta-analysis does not support an association between diets high in glycemic index, glycemic load, total carbohydrates or sucrose and pancreatic cancer risk. The finding of an increased risk with fructose intake warrants further investigation in studies with better adjustment for confounding and in non-American populations.