Nutrient-based dietary patterns and nasopharyngeal cancer: evidence from an exploratory factor analysis.

BACKGROUND: To our knowledge, no study assessed the association between dietary patterns and nasopharyngeal carcinoma (NPC) in low-incidence areas. METHODS: We examined this association in a hospital-based case-control study carried out in Italy between 1992 and 2008, including 198 incident NPC cases and 594 controls. A posteriori dietary patterns were identified through principal component factor analysis performed on 28 nutrients and minerals derived from a 78-item food-frequency questionnaire. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using unconditional multiple logistic regression models on tertiles of factor scores. RESULTS: We identified five dietary patterns named Animal products, Starch-rich, Vitamins and fibre, Animal unsaturated fatty acids (AUFAs), and Vegetable unsaturated fatty acids (VUFAs). The Animal product (OR=2.62, 95% CI=1.67-4.13, for the highest vs lowest score tertile), Starch-rich (OR=2.05, 95% CI=1.27-3.33), and VUFA (OR=1.90, 95% CI=1.22-2.96) patterns were positively associated with NPC. The AUFA pattern showed a positive association of borderline significance, whereas the Vitamins and fibre pattern was nonsignificantly but inversely associated with NPC. CONCLUSIONS: These findings suggest that diets rich in animal products, starch, and fats are positively related to NPC risk in this low-incidence country.