Residential Exposure to Ambient Hazardous Air Pollutants with Estrogen Disrupting Effects and Breast Cancer Risk in the California Teachers Study

Abstract

Residential Exposure to Ambient Hazardous Air Pollutants with Estrogen Disrupting Effects and Breast Cancer Risk in the California Teachers StudyAbstract Number:1797 Ruiling Liu*, David O Nelson, Susan Hurley, Andrew Hertz, Peggy Reynolds Ruiling Liu* Cancer Prevention Institute of California, United States, E-mail Address: [email protected] Search for more papers by this author , David O Nelson Cancer Prevention Institute of California, United States, E-mail Address: [email protected] Search for more papers by this author , Susan Hurley Cancer Prevention Institute of California, United States, E-mail Address: [email protected] Search for more papers by this author , Andrew Hertz Cancer Prevention Institute of California, United States, E-mail Address: [email protected] Search for more papers by this author , and Peggy Reynolds Cancer Prevention Institute of California, United States, E-mail Address: [email protected] Search for more papers by this author AbstractSome studies show increased breast cancer risk from exposure to xenoestrogens, but few have explored exposures via ambient air, which could impact large populations. We explored the association between breast cancer and residential exposure to estrogen disrupting compounds (EDCs) listed as hazardous air pollutants (HAPs) by the U.S. EPA in a large cohort of female California teachers. Participants consisted of 112,379 women who were free of breast cancer and lived at a California address in 1995. Between 1996 and 2010, 5,359 invasive breast cancer cases were identified via linkage to the California Cancer Registry. 10 HAPs that were included in the U.S. EPA 2002 HAPs list were identified as EDCs based on two published endocrine disrupting chemical lists and literature review. Census-tract EDC levels from the U.S. EPA’s 2002 NATA database were assigned to participants’ baseline addresses. Cox proportional hazards models were used to estimate hazard ratios associated with each EDC and a summary measure of 8 estrogenic HAPs, adjusting for age, race, socioeconomic status and known breast cancer risk factors. No significant associations were found for exposure to the 8 estrogenic HAPs in total, the anti-estrogenic selenium compound or the mixture of diesel emissions, nor were significant linear trends observed. Compared to women with exposure in the lowest quintile, modestly increased risks (p<0.05) were observed for some quintiles of exposure for 4-nitrophenol and dimethylformamide in pre/peri menopausal women, for cadmium compounds and chlorobenzilate in postmenopausal women, and for dimethylformamide, biphenyl and cadmium compounds in women with hormone responsive breast tumors. These preliminary results suggest some associations between breast cancer and residential exposure to ambient environmental estrogens, with potential non-monotonic effects even at low-dose exposures. Future studies are required to exam the dose- response relationship and possible mechanisms.