Abstract LB-283: A prospective study of breast cancer risk associated with occupational exposure to potentially endocrine disrupting compounds

Abstract

Abstract Background: Endocrine disrupting compounds, exogenous substances that interfere with normal endocrine functions, have been suspected to play a role in the etiology of breast cancer. The purpose of this study was to investigate the relationship between occupational exposure to potential endocrine disrupting compounds and breast cancer risk among women enrolled in the Sister Study, a prospective cohort study of US and Puerto Rican women designed to examine the genetic and environmental risk factors for breast cancer. Methods: Over 50,000 women aged 33-74 enrolled in the Sister Study between 2004 and 2009. A comprehensive baseline questionnaire included questions about occupational exposures, including ever use and duration and frequency of use of nine agents containing potential endocrine disrupting compounds: Dyes or Inks, Gasoline or other Petroleum Products, Glues or Adhesives, Lubricating Oils, Metals, Paints, Pesticides, Organic Solvents, and Stains. Cumulative lifetime exposure to each potential endocrine disruptor was estimated and classified into quartiles. Study participants were prospectively followed from baseline until breast cancer diagnosis, death, or end of follow-up. Multivariable Cox proportional hazards regression was used to assess the impact of level of exposure (comparing each quartile of exposure with never exposure) to each of these compounds on breast cancer risk, adjusting for established breast cancer risk factors. Results: Among the 47,755 women in the Sister Study with an occupational history, a total of 1798 cases of invasive breast cancer were diagnosed. Compared to their respective never exposure groups, an elevated risk of estrogen-receptor positive breast cancer was observed for women in the top quartile of occupational exposure to Dyes or Inks (HR: 1.7, 95%CI: 1.1-2.8). Non-significantly elevated risks were observed for women in the top quartile of occupational exposure to Gasoline or other Petroleum Products (HR: 1.7, 95%CI: 1.0-2.9) and Metals (HR: 1.5, 95%CI: 0.9-2.8). Conclusions: Results suggest that exposure to occupational dyes or inks may influence breast cancer risk. Dyes and inks contain compounds with endocrine disrupting properties, including organic compounds and heavy metals. Further studies are necessary to elucidate the role of these potential endocrine disrupting compounds in breast cancer. Citation Format: Christine C. Ekenga. A prospective study of breast cancer risk associated with occupational exposure to potentially endocrine disrupting compounds. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr LB-283. doi:10.1158/1538-7445.AM2014-LB-283