Dietary Patterns in Italy and the Risk of Renal Cell Carcinoma

Background: Conclusive evidence on foods, nutrients, or dietary patterns and the risk of renal cell carcinoma (RCC) is lacking in the literature. Methods: We considered data from an Italian hospital-based case-control study (1992-2004) on 767 incident RCC cases and 1534 controls. A posteriori dietary patterns were identified by applying principal component factor analysis on 28 nutrients derived from a 78-item food-frequency questionnaire. We estimated the odds ratios (ORs) of RCC and corresponding 95% confidence intervals (CIs) for each quartile category (compared to the lowest one) using conditional multiple logistic regression models providing adjustment for major confounding factors. Results: We identified four dietary patterns, named "Animal products", "Starch-rich", "Vitamins and fiber", and "Cooking oils and dressings". Higher intakes of the "Starch-rich" pattern were positively associated with RCC risk (OR = 1.38, 95% CI: 1.04-1.82 for the highest quartile, p = 0.018). The association was inverse with the "Cooking oils and dressings" pattern (OR = 0.61, 95% CI: 0.47-0.80, p < 0.001), whereas no association was found with "Animal products" and "Vitamins and fiber" patterns. Conclusions: Higher intakes of starch-related foods may increase RCC risk, whereas consumption of olive and seed oils may favorably influence RCC risk.