Background: The ability of dietary carbohydrates to affect blood glucose and insulin levels by dietary carbohydrates is best measured by the glycemic index (GI) and glycemic load (GL) which have been directly associated with risk of several chronic conditions, including cancer.
Patients and methods: Three case-control studies were conducted between 1992 and 2000 in Italy. The first one included 598 hospital patients with incident, histologically confirmed oral and pharyngeal cancer and 1491 controls admitted to the same hospital networks for acute, non-neoplastic diseases; the second study included 304 subjects with squamous cell oesophageal cancer and 743 controls; the third one included 460 cases with laryngeal cancer and 1088 controls. All subjects were interviewed using a validated food frequency questionnaire.
Results: The odds ratios (OR) of upper aero-digestive tract neoplasms for the highest versus the lowest quintile of dietary GI and GL were 1.5 (95% confidence interval [CI]: 1.1-2.0) and 1.8 (95% CI: 1.1-2.9), respectively. The associations were in the same direction for various cancer sites. The ORs were apparently stronger in women, in those with high body mass index and reporting low alcohol consumption.
Conclusions: This study supports the hypothesis that high dietary GI and GL are associated with cancers of the upper aero-digestive tract.