Dietary patterns and the risk of postmenopausal breast cancer in a German case-control study

Dietary patterns have been inconsistently associated with breast cancer risk. We assessed dietary patterns in association with postmenopausal breast cancer risk using an exploratory approach. In a case-control study on postmenopausal breast cancer risk, including incident breast cancer cases (aged 50-74 years) diagnosed between 2002 and 2005 in Germany, information from a food frequency questionnaire among 2,884 cases and 5,509 controls was used for the identification of dietary patterns using principal component factor analysis. Unconditional logistic regression was performed to calculate odds ratios (ORs) adjusted for potential confounders for the highest versus the lowest quintile of dietary pattern score. Two major dietary patterns were identified, i.e., a "healthy" (including high vegetable and vegetable oil intake) and an "unhealthy" (including high meat and deep-frying fat intake) dietary pattern. Overall, no associations between the dietary patterns and breast cancer risk were observed (OR = 1.04, 95% confidence interval (CI) = (0.88, 1.23) and OR = 0.96, 95% CI = (0.81, 1.13), respectively). Associations did not differ by ER/PR status, body mass index, hormone replacement therapy use, education, energy intake, and smoking status. In conclusion, we did not find an association of a "healthy" or "unhealthy" dietary pattern with postmenopausal breast cancer risk.