Identification of a dietary pattern characterized by high-fat food choices associated with increased risk of breast cancer: the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam Study.

Epidemiological studies conducted thus far have mainly used a single-nutrient approach which may not be sufficient in detecting diet-cancer relationships. The aim of the study was to examine the association of a food pattern based on explained variations in fatty acid intake by means of reduced rank regression with breast cancer risk. Study participants were female subjects (n 15,351) of the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam Study free of cancer at baseline and with complete dietary and outcome information followed for an average of 6.0 years. Among those, 137 incident cases of invasive breast cancer were identified. We identified a food pattern characterized by low consumption of bread, and fruit juices, and high consumption of processed meat, fish, butter and other animal fats, and margarine explaining >42 % of total variation in fatty acid intake (SFA, MUFA, n-3 PUFA, n-6 PUFA). Intake of all four fatty acid fractions was positively associated with the pattern score. Adherence to this food pattern adjusted for covariates was associated with a two-fold risk (hazard ratio 2.00; 95 % CI 1.30, 3.09) of breast cancer comparing extreme tertiles of the pattern score. There was no evidence of effect modification by menopausal status, overweight status and use of hormone replacement therapy, respectively. In conclusion, a food pattern characterized by high-fat food choices was significantly associated with increased risk of breast cancer. Given that the food pattern was high in all fatty acid fractions, we found evidence for total dietary fat rather than for specific fatty acids to be associated with breast cancer risk.