Dietary patterns identified using factor analysis and prostate cancer risk: A case control study in Western Australia

PURPOSE: Dietary patterns offer an alternative method for analyzing dietary intakes that take into account the whole diet. We investigated empirical dietary patterns and prostate cancer risk in Western Australia (WA) using a population-based case-control study. METHODS: Incident prostate cancer cases were identified via the WA Cancer Registry. Controls were sourced from the WA electoral roll, frequency matched on age. A food frequency questionnaire (FFQ) estimated usual dietary intake from 10 years earlier. Factor analysis identified dietary patterns in FFQ data. Effects of independent dietary patterns on prostate cancer risk were examined using unconditional logistic regression, adjusting for potential confounders. RESULTS: A total of 546 cases and 447 controls provided data. Three distinct dietary patterns were identified, which we labeled vegetable, Western, and health-conscious. An increased risk for prostate cancer was observed with the Western pattern, which consisted of high intakes of red and processed meats, fried fish, hamburgers, chips, high-fat milk, and white bread. Men in the highest quartile for Western pattern score had an odds ratio of 1.82 (95% confidence interval 1.15-2.87, trend p = 0.02). Results were similar for aggressive cases and attenuated for non-aggressive cancers. CONCLUSIONS: A western style diet may lead to increased risks for prostate cancer, especially aggressive prostate cancer.