Abstract B96: Antioxidants and cancer of the endometrium: Results from a population-based case-control study in New Jersey

Abstract

Abstract Endometrial cancer is the most common gynecologic malignancy in the United States and the fourth most common cancer among women. There is suggestive but limited evidence that dietary antioxidants may be associated with protective effects. We therefore sought to investigate the role of total dietary antioxidant capacity and of individual antioxidants (including vitamin E, vitamin C, beta-carotene, selenium, lycopene, and lutein) on endometrial cancer risk in a population-based case-control study in New Jersey. A total of 417 endometrial cancer patients and 310 controls from the Estrogen, Diet, Genetics and Endometrial cancer (EDGE) study were included in the analysis. Cases were women with newly diagnosed histologically confirmed endometrial cancer, ages 21 years and older who spoke English or Spanish and resided in six counties of NJ. Controls were women residing in the same geographic area who had not had a prior hysterectomy. Dietary information was ascertained using the Block food frequency questionnaire (FFQ), and total antioxidant indices were constructed by linking data from the USDA Oxygen Radical Absorbance Capacity (ORAC) Database and the University of Oslo's Antioxidant Food Database (AFD) to FFQ-derived estimates of intake. Odds ratios and 95% confidence intervals were derived using multivariate logistic regression controlling for major endometrial cancer risk factors. Using antioxidant capacity estimates derived from the ORAC database, after adjusting for major covariates, we found decreased risks for the highest tertile of total phenolic intake compared to the lowest (OR: 0.62; 95%CI: 0.39−0.98) and suggested decreased risks for total lipophilic antioxidant intake (OR: 0.74; 95%CI: 0.49−1.13). Results for total antioxidant intake based on the AFD, which utilized the ferric reducing ability of plasma (FRAP) assay to assess antioxidant capacity, were weaker. A suggested decreased risk with the highest tertile compared to the lowest of dietary selenium (OR: 0.64; 95%CI: 0.37 − 1.10), dietary lycopene (OR: 0.74; 95%CI: 0.48 − 1.12), and dietary vitamin E (OR: 0.78; 95%CI: 0.46 − 1.33), were observed, however none reached statistical significance. Any supplemental vitamin E use was associated with an increased risk (OR: 1.43; 95%CI: 1.00−2.04). To our knowledge, this is the first study to investigate total antioxidant intake and endometrial cancer risk. Results from this study suggest that components of dietary antioxidant intake that have received little attention, mainly total phenolics, total lipophilic antioxidant intake, and dietary selenium, may be associated with decreased risks of endometrial cancer. Our findings contribute to the growing pool of evidence that phenolics may have a protective effect on oxidative stress-induced disease. Additionally, our findings show that antioxidant capacity values from differing assays may not be comparable, and that antioxidant supplement use may be associated with increased risks. Our findings warrant further research to better understand the role of phenolics, lipophilic antioxidants, and dietary selenium in endometrial cancer prevention. Citation Information: Cancer Prev Res 2011;4(10 Suppl):B96.