Dietary Patterns in Italy and the Risk of Renal Cell Carcinoma

Abstract

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.

A Posteriori Dietary Patterns and Rheumatoid Arthritis Disease Activity: A Beneficial Role of Vegetable and Animal Unsaturated Fatty Acids

“…The current study has strengths and limitations. Among the strengths, we expanded the list of nutrients used in previous papers of our group on several cancer sites (e.g., [ 43 , 44 , 45 ]) to include nutrients such as EPA, DHA, lignans, flavonoids, phenolic acids, and tyrosols, which are likely to be involved in RA development or disease activity [ 6 , 7 , 8 , 9 , 13 , 14 ]. Other nutrients could be added to our list.…”

“…They quantify the degree of adherence of each subject’s diet to each identified DP. Factor scores were computed using the weighted least squares method and, by design, they are continuous measures with mean equal to 0 [ 43 , 44 , 45 ].…”

“…To evaluate the internal reproducibility of the identified DPs [ 43 , 44 , 45 ], we performed additional analyses using: 1. different estimation methods (namely principal axis factor analysis with generalized least squares estimation method, and maximum likelihood factor analysis, after logarithmic transformation of the original nutrients to improve adherence to the Normality assumption), and 2. a different procedure for estimating factor scores (namely multiple regression method) [ 41 ]. We also carried out two separate analyses on females and males.…”

“…To evaluate factor reliability and refine the identified DPs [ 43 , 44 , 45 ], we calculated the standardized Cronbach’s coefficient alpha for those nutrients with a factor loading ≥ 0.40 in absolute value on any factor [ 46 ]. For each factor we computed the overall alpha coefficient and all available coefficient alphas when-item-deleted, which assessed the importance of each nutrient within the corresponding DP.…”

“…To further interpret the identified DPs [ 43 , 44 , 45 ], we calculated the Spearman rank correlation coefficients between the continuous factor scores derived from principal component factor analysis and the daily intake of 33 selected food groups and condiments, defined on the same data and derived from the original 110 food items.…”