Serum Concentrations of Polybrominated Diphenyl Ethers (PBDEs) and Breast Cancer Risk in Young Women: Results from the Ontario Environment and Health Study

Abstract

Polybrominated diphenyl ethers (PBDEs) are brominated flame retardants commonly used in a wide range of household products and electronic devices. Some PBDE congeners have endocrine-disrupting properties, suggesting a potential role in the development of hormonally-related cancers. This is the first study to investigate serum PBDE levels in relation to breast cancer diagnosed in women under 45 years of age.Serum samples were collected from 305 incident breast cancer cases (284 pre-menopausal), identified in the Ontario Cancer Registry between 2012 and 2015, and 144 controls. Gas chromatography/electron ionization-mass spectrometry was used to quantify 8 congeners (ng/mL): BDE-28, BDE-47, BDE-85, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183. Samples in which congeners were not detected or had concentrations below the method detection limit were considered unexposed. For each congener odds ratios (OR) and their 95% confidence intervals were estimated using logistic regression, with adjustment for age, serum lipids, body-mass index 2 years earlier, parity, and date of sample collection.Detection prevalence for each congener was as follows: BDE-47 (52.8%), BDE-153 (19.4%), BDE-99 (11.8%), BDE-100 (9.8%), BDE-28 (4.5%), BDE-183 (4.5%), BDE-154 (1.8%). BDE-47 detection was positively associated with breast cancer status (OR=1.65, 95% CI: 0.99-2.74), but this relationship was significant only in pre-menopausal women (OR=1.73, 1.02-2.94). Suggestive associations were also observed for BDE-153 (OR=1.63, 0.89-2.98) and several related congeners. Combined exposure to BDE-153, -154, and -183 was significantly associated with breast cancer risk (OR=1.98, 1.11-3.56; pre-menopausal: OR=2.19, 1.17-4.11). Non-linear relationships with BDE concentrations were evaluated using smoothing splines, but no significant associations (p<0.05) with case status were observed.Our preliminary findings suggest a possible association between serum PBDE levels and risk of breast cancer in young women.