Diabetes risk reduction diet and the risk of oral and pharyngeal cancer

Purpose Diabetes has been associated with an increased risk of several neoplasms, including oral and pharyngeal cancer (OPC). We evaluated whether adherence to a diabetes risk reduction diet (DRRD) was inversely associated with the risk of OPC. Methods We analyzed data from a multicentric case-control study conducted between 1991 and 2009 in Italy. The study included 942 OPC cases and 2492 controls. A food frequency questionnaire was used to gather information on subjects' usual diet. A DRRD score was computed based on 8 dietary components: cereal fiber, coffee, total fruit, nuts, polyunsaturated to saturated fatty acids ratio, dietary glycemic index, red/processed meat and sugar-sweetened beverages/fruit juices. Higher score corresponded to higher adherence to DRRD. Odds ratios (ORs) of OPC for the DRRD score were estimated using multiple logistic regression models. Results We found an inverse association between DRRD and OPC risk. We found a 53% lower risk of OPC (OR: 0.47;95% CI: 0.35-0.64) for the highest versus the lowest quintile of the score. There was a 60% lower risk for oral cavity cancer (OR: 0.40; 95% CI: 0.28-0.59) and 48% for hypopharyngeal cancer (OR: 0.52; 95% CI: 0.29-0.94). The results were consistent across subgroups of sex, age and other selected covariates. Conclusion These findings indicate a favourable role of adherence to a DRRD on the risk of OPC, which may involve additional factors besides the control of glucose metabolism.