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.