Persistent Organic Pollutants and Breast Cancer Risk
Creators: name: University Of California Office Of The President
Publisher: name: University of California Office of the President
publisherIdentifier: https://ror.org/00dmfq477
publisherIdentifierScheme: ROR
Year: 2024

description: Persistent Organic Pollutants (POPs) are a large, diverse group of synthetic toxic compounds that include organochlorine pesticides and some industrial chemicals. Originally introduced during the post WWII industrial boom, many of the older POPs, including DDT and polychlorinated biphenyls (PCBs) were banned in the 1970s due to concerns about health effects. These compounds don’t easily break down; they accumulate in the food chain, including people’s body fat. Consequently, most Americans today have detectable levels of these chemicals in their bodies. Polybrominated diphenyl ethers (PBDEs) and other brominated flame retardants (BFRs) are a newer class of POPs, initially introduced in the late 1970s as flame retardant additives to consumer and building products. The concentrations of these newer POPs in human tissue are increasing at an alarming rate and Californians have some of the highest levels in the world. While many of the older POPs are known or suspected carcinogens, their role in the development of breast cancer is uncertain; the health effects of the newer POPs are virtually unknown. 
 
 
 
 
 
 
 
 The primary objective of this study is to investigate the risk of breast cancer associated with both the older and newer POPs among participants in the California Teachers Study (CTS), a large on-going study of breast cancer among 133,479 female California professional school employees. We will also look for disparities in, and predictors of, body burden levels of these compounds and explore potentially important windows of susceptibility. Capitalizing on the unique resources collected over the 15 years since the CTS’ inception, this study will measure the levels of POPs in blood collected for two studies already underway. To identify disparities in, and predictors of, body burden levels of PBDEs/BFRs, we will utilize the approximately 360 blood specimens to be collected from CTS participants in 2010. A geographic information system (GIS) will be used to link the residential location of CTS members’ homes to the location of waste processing and manufacturing sites that may serve as sources of PBDE/BFR exposures. Survey and census data will be used to explore behavioral and sociodemographic predictors of body burden levels. Study participants are racially and ethnically diverse and from both rural and urban areas, so that analyses may identify disparities in exposure to these compounds. 
 
 
 
 
 
 
 
 These preliminary analyses will help us optimize selection of study subjects for the breast cancer risk analysis. This will be conducted among 2,000 CTS participants who have provided a blood specimen, 1,000 who will have been diagnosed with breast cancer and 1,000 women who remained breast cancer-free (controls) between 2007 and 2013. Concentrations of 15 PCBs, 4 organochlorine pesticides, 11 PBDEs, and 10 BFRs will be measured in their blood. Statistical models will be used to compare the levels of these POPs in women with breast cancer to the control women. Survey information will be used to account for differences in other known risk factors. Additional analyses will evaluate whether certain women may be especially susceptible to risks associated with these exposures due to the type of tumor they have, or by virtue of selected behavioral or genetic characteristics. For a subset of the CTS cohort, we will use questionnaire and birth file data to enhance exposure estimates for earlier time periods that may represent windows of increased vulnerability to the effects of these compounds.
 
 
 
 
 
 
 
 This study is designed to overcome many limitations common to prior studies. By using the large number of biospecimens already being collected through the CTS parent grant, and with Dr. Petreas’ expertise in measuring multiple POPs in a single sample, our study offers an outstanding opportunity to investigate multiple compounds and susceptible subpopulations or potentially important windows of susceptibility. Advanced statistical techniques from genomics offer an innovative approach to the complexities of POPs exposures, which tend to be highly correlated and may act either synergistically or antagonistically to influence risk. This study could be the first large-scale epidemiologic study to evaluate the potential link between PBDEs/BFRs and breast cancer, as well as identify disparities in and determinants of exposure — information critical to public health and regulatory actions aimed at curbing such exposures. Finally, it directly addresses the ongoing concerns of breast cancer and environmental advocates about the role of these chemicals in breast cancer.
 
 
 
 
 
 
 
 Publications: 
 
 
 
 Time Trends in Per- and Polyfluoroalkyl Substances (PFASs) in California Women: Declining Serum Levels, 2011–2015
 
 
 
 
 
 
 
 
 
 
 
 Declines in serum PBDEs in older California women may have reached a plateau (2011-2015)