Abstract 2828: Examination of two approaches to assess dietary patterns in relation to colorectal cancer risk
Authors: Miller Paige E. , Lazarus Philip , Lesko Samuel M. , Muscat Joshua E. , Harper Gregory , Cross Amanda J. , Sinha Rashmi , Ryczak Karen , Escobar Gladys , Hartman Terry J. 
Published: February 2011

Abstract
The investigation of dietary patterns presents a promising approach that may prove informative in the evaluation of diet and cancer risk. Most studies have derived patterns by measuring compliance with pre-established dietary guidance (hypothesis-oriented) or empirical methods such as principal components analysis (PCA). The objective of the present study was to compare the risk of colorectal cancer (CRC) associated with dietary patterns identified by both methods. The study sample included 431 incident CRC cases and 726 healthy controls participating in a population-based case-control study in Northeastern Pennsylvania. Participants completed a modified Diet History Questionnaire (DHQ) developed by the National Cancer Institute; the DHQ was reviewed during an in-person interview. PCA was performed to identify sex-specific dietary patterns, and the Healthy Eating Index-2005 (HEI-05) was calculated to assess participant adherence to the 2005 Dietary Guidelines. Multivariate logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between empirically-derived and index-based patterns with CRC. PCA identified three major dietary patterns among men, which were labeled according to the food groups with the greatest factor loadings (fruits/vegetables, meat/potatoes, and alcohol/sweetened beverages); two of these patterns were also identified among women (fruits/vegetables and meat/potatoes). The fruits/vegetables pattern was high in nuts and legumes, low-fat dairy in women, and fish in men. The meat/potatoes pattern was characterized by greater consumption of high-fat dairy, condiments, sweets, and refined grains. The fruits/vegetables pattern was inversely related to CRC among men (OR=0.38, 95% CI: 0.21-0.70) and women (OR=0.41, 95% CI: 0.23-0.75). Conversely, the meat/potatoes pattern was positively associated with CRC in women (OR=2.15, 95% CI: 1.06-4.37), but did not reach statistical significance in men. There was no evidence of an association between the alcohol/sweetened beverage pattern and CRC in men. Comparable protective effects of greater HEI-05 scores were found for both men and women (OR=0.52, 95% CI: 0.30-0.93; OR=0.44, 95% CI: 0.25-0.78, respectively). In conclusion, both methods may be informative in studies of diet and cancer risk; the more useful tool may depend upon the specific goals of the investigation. Index-based approaches are valuable in assessing compliance with recommended dietary patterns, whereas data-driven analyses are useful in examining actual dietary behavior within a population. Our findings indicate that following the U.S. Dietary Guidelines or a primarily plant-based dietary pattern that includes low-fat dairy and fish may reduce CRC risk, whereas a meat-centered diet rich in high-fat and high-sugar foods may increase risk.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2828.