Polybrominated diphenyl ethers (PBDEs) are flame retardants added to consumer products including electronics, polyurethane foam and appliances. They are persistent chemicals that have contaminated the food chain. Some are endocrine disruptors and may increase the risk of certain cancers, including breast cancer.
Our aim was to develop a PBDE exposure assessment strategy for use in epidemiology studies, including the Ontario Environment and Health Study, a population-based case-control study of breast cancer in Canadian women, aged 18-44 years.
To evaluate the routes and sources of PBDE exposures, the published and grey literature were searched. The literature was summarized and exposure sources were prioritized. Previously developed questionnaires and exposure assessment strategies were reviewed.
Dust ingestion, dermal absorption, and hand-to-mouth contact were important exposure routes. Dietary sources include poultry, red meat, fatty fish, and fish oils. Occupational sources and air travel contribute to exposure. A questionnaire was developed to obtain occupational/environmental exposures and housing characteristics. To capture dietary sources, the Block 2005 food frequency questionnaire was modified, and a PBDE database will be developed. To evaluate absorbed dose, serum and urine will be collected and placed in a Biobank. Serum will be analyzed for PBDE congeners. We plan to collect air, dust, and surface wipes in 51 homes, to be used for validation.
A comprehensive exposure assessment strategy allows us to: evaluate associations between PBDE exposures and breast cancer (using serum biomarkers), understand sources of exposure measurement error (based on questionnaires), and identify important sources of human exposure.