Abstract 976: Consumption of vitamins and calcium reduces breast cancer risk by their regulation of the DNA repair capacity

Abstract

Abstract Background- Breast cancer (BC) is the most common cancer in women with over one million new cases diagnosed annually worldwide. The capacity of the DNA to repair itself (DRC) is a complex biological process involving over 200 proteins. This process involves at least five pathways and is critical in maintaining genomic stability. The objective of this study was to examine the association of DRC and BC risk in terms of consumption of vitamin and calcium supplements by means of a large scale case-control study. Methods.- This was an incident-case case-control study design involving Puerto Rican women. The selection of potential predictors under study was based on previous published research in BC including information on vitamins, calcium, and variables that could provide an estimate of BC risk including age, BMI, family history, gynecological history, hormonal and environmental factors. The host reactivation assay with a luciferase reporter gene was used to measure the DRC in the lymphocytes from all participants. Cases were compared to controls, regarding diet supplement intake, DRC, and other selected covariates. The crude and multiple logistic regression adjusted Odds Ratio (OR) were used as measures of association and the 95% confidence interval of the OR was utilized to asses the precision of this estimate. Results.- A total of 268 breast cancer cases and 457 controls were included in this analysis. Statistically significant associations were found between BC and ageing, low DRC levels, family history of BC, and no breastfeeding. Vitamins and calcium intake were found to be protective reducing 30% and 40% the odds of having BC respectively. Calcium reduced considerably its protective effect becoming negligibly and not statistically significant when DRC was included in the logistic regression model. This suggests that DRC explains this association. In contrast, vitamin's intake did not show an important change in the association with BC when adjusting for DRC. Calcium and vitamins’ intake were strongly associated with higher levels of DRC. Discussion.- Vitamins and calcium intake are protective for breast cancer and are associated with higher DRC levels. Vitamins’ intake is an independent protective factor for BC while the protective effect of calcium may be explained by an increased DRC. DRC can be used to monitor the protective effect of calcium in terms of breast cancer risk. This study is supported by grants from the NCI Center to Reduce Health Disparities and NIH-MBRS Program grant #: S06 GM008239-23. 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 976.