Background: There have been several studies on diet and gastric cancer, but only a few investigations have considered the role of dietary patterns.
Methods: We investigated gastric cancer risk in relation to dietary patterns in a case-control study conducted in northern Italy between 1997 and 2007, including 230 patients with incident, histologically confirmed gastric cancer and 547 frequency-matched controls, admitted to the same hospitals as cases, with acute nonneoplastic conditions. Dietary habits were investigated through a validated food frequency questionnaire including 78 foods and beverages. We identified a posteriori dietary patterns on a selected set of 28 micro- and macro-nutrients through an exploratory principal component factor analysis. We estimated the odds ratios (OR) and the corresponding 95% confidence intervals (95% CI) using conditional logistic regression models on quartiles of factor scores.
Results: We identified four major dietary patterns, named "animal products", "vitamins and fiber", "vegetable unsaturated fatty acids", and "starch-rich". We observed a positive association between gastric cancer risk and the "animal products" (OR, 2.13; 95% CI, 1.34-3.40, for the highest versus the lowest score quartile) and the "starch-rich" (OR, 1.67; 95% CI, 1.01-2.77) dietary patterns. The "vitamins and fiber" pattern (OR, 0.60; 95% CI, 0.37-0.99) was inversely associated with gastric cancer, whereas no significant association emerged with the "vegetable unsaturated fatty acids" pattern (OR, 0.89; 95% CI, 0.56-1.42).
Conclusions: Our analysis suggests a protective effect against gastric cancer risk of dietary patterns rich in fruits and vegetables, and a positive association of dietary patterns rich in meats and animal fats and starchy foods.