Abstract 3851: Low educational level is associated with a reduced DNA repair capacity and higher risk of breast cancer
Authors: Morales Luisa , Bayona Manuel , Ortiz Carmen , Adams Damian , Alvarez-Garriga Carolina , Matta Jaime L. 
Published: August 2015

BACKGROUND: Breast Cancer (BC) is the leading cause of cancer deaths among females in Puerto Rico. Educational level is well established as a modifier of cancer risk. We have undertaken a large population study and have shown that a low DNA Repair Capacity (DRC) is an important risk factor for BC. It is well established that DRC is regulated by genetic, epigenetic and environmental factors. We have investigated the relationship between educational level and DRC.

The purpose of this study was to evaluate the role of educational level as a modifier of the association between DRC and risk of BC in Puerto Rican women. METHODS: A total of 488 women with histopathologically confirmed BC and 607 controls were selected for the analysis. DRC was measured in lymphocytes using a host cell reactivation assay. Pathology reports were used to obtain tumor size. DRC levels were divided into low, medium and high using tertiles. Multiple logistic regression was used to assess the association among educational level and BC risk factors adjusted by DRC. For the analysis of tumor size and DRC, educational levels were divided into primary education, high school, and associate or more. Analysis of variance was performed using the Kruskal-Wallis test. RESULTS: Women with lower educational level (elementary education) had significantly higher risk of BC (OR: 5.9, 95%CI: 2.3, 14.9) followed by high school (OR: 1.4, 95%CI: 1.1, 2.1) and associate degree (OR: 1.4, 95%CI: 0.9, 2.2) using bachelor's degree as a referent. Women with low education had 8.9 times the odds of having low DRC (95%CI: 5.2, 15.2), while women with high educational level had 11.7 times the odds for a low DRC (95%CI: 7.7, 17.7). The association and tumor size (cm) and educational level showed that as educational level increased, women had smaller tumor sizes (Kruskal-Wallis test p = 0.031). CONCLUSIONS: This study showed that women with the lowest levels of education, in general, had a lower DRC and significantly higher risk of BC and of having larger breast tumors when compared to controls. This study provides new insights as to how educational level can influence BC risk. This association is controversial because some studies attribute a high educational level to high risk of BC while others present the opposite. Because our study uses a biological variable (DNA repair) to measure risk, it reduces ambiguity in terms of the criterion to estimate risk. Those with the highest levels of education had smaller tumors; therefore consequently better chances for early treatment and increased chances of survival. Because education is a modifiable lifestyle factor, this study provides data that can be utilized to identify women with a higher risk of developing BC in order to design more effective BC screening, and diagnosing BC an earlier stage. Supported by grants from the NCI Diversity Training Branch through the NIH-MBRS Program grants S06 GM008239-20, 9SC1CA182846-04 to PSMHS through JM and MBRS-RISE GM082406 through CO.

Citation Format: Luisa Morales, Manuel Bayona, Carmen Ortiz, Damian Adams, Carolina Alvarez-Garriga, Jaime L. Matta. Low educational level is associated with a reduced DNA repair capacity and higher risk of breast cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3851. doi:10.1158/1538-7445.AM2015-3851