Background: The Mediterranean diet has been shown to have a beneficial role on various neoplasms, but data are scanty on pancreatic cancer.
Methods: We analysed data from two case-control studies conducted in Italy between 1983 and 2008, including 362 and 326 pancreatic cancer cases and 1552 and 652 hospital-controls, respectively. A Mediterranean Diet Score (MDS) summarising major characteristics of the Mediterranean diet was used in the two studies separately and overall. Two further scores of adherence to the Mediterranean diet were applied in the second study only, the Mediterranean Dietary Pattern Adherence Index (MDP) and the Mediterranean Adequacy Index (MAI).
Results: Odds ratios (ORs) for increasing levels of the scores (i.e., increasing adherence) were estimated using multiple logistic regression models. Odds ratio for a MDS score ≥6 compared with <3 was 0.57 (95% confidence interval (CI) 0.34-0.95) in the first study, 0.51 (95% CI 0.29-0.92) in the second study, and 0.48 (95% CI 0.35-0.67) overall. A trend of decreasing risk was observed also for the MDP and MAI the ORs for the highest vs the lowest quintile being 0.44 (95% CI 0.27-0.73) for MDP and 0.68 (95% CI 0.42-1.11) for the MAI. The results were consistent across strata of age, sex, education, body mass index, alcohol drinking, tobacco smoking, and diabetes.
Conclusion: Our study provides evidence that a priori-defined scores measuring adherence to the Mediterranean diet are favourably associated with pancreatic cancer risk.