Nutrient dietary patterns and the risk of breast and ovarian cancers

The issue of diet and breast and ovarian cancers has been considered in terms of foods and nutrients, but rarely in terms of dietary patterns. We examined the associations between dietary patterns and breast and ovarian cancers in 2 Italian multicentric case-control studies. Cases were 2,569 breast cancers and 1,031 ovarian cancers hospitalized in 4 Italian areas between 1991 and 1999. Controls were 3,413 women from the same hospital network. Dietary habits were investigated through a validated food-frequency questionnaire. Dietary patterns were identified on a selected set of nutrients through principal component factor analysis. Odds ratios (OR) and 95% confidence intervals (CI) for both cancers were estimated using unconditional multiple logistic regression models on quartiles of factor scores and continuous factor scores. We identified 4 major dietary patterns named Animal products, Vitamins and fiber, Unsaturated fats and Starch-rich. The animal products pattern and the unsaturated fats pattern were inversely associated with breast cancer (OR = 0.74, 95% CI: 0.61-0.91 and OR = 0.83, 95% CI: 0.68-1.00, respectively, for the highest consumption quartile), whereas the starch-rich pattern was directly associated with it (OR = 1.34, 95% CI: 1.10-1.65). The vitamins and fiber pattern was inversely associated with ovarian cancer (OR = 0.77, 95% CI: 0.61-0.98), whereas the starch-rich pattern was directly associated with it (OR = 1.85, 95% CI: 1.37-2.48). In conclusion, the starch-rich pattern is potentially an unfavorable indicator of risk for both breast and ovarian cancers, while the animal products and the vitamins and fiber patterns may be associated with a reduced risk of breast and ovarian cancers, respectively.