Adipose levels of polybrominated diphenyl ethers and risk of breast cancer.

We conducted a case-control study to evaluate the risk of breast cancer associated with adipose concentrations of polybrominated diphenyl ethers (PBDEs) among women undergoing surgical breast biopsies in the San Francisco Bay Area of California (n=78 cases; 56 controls). Adipose tissue was analyzed for the five major congeners of PBDEs. Unconditional logistic regression was used to estimate age- and race-adjusted exposure-specific odds ratios (ORs) and 95% confidence intervals (95% CI). Adipose levels of PBDEs were among the highest ever reported. Adjusted ORs for the highest compared with lowest levels of exposures were as follows: 0.56 (95% CI 0.19-1.68) for BDE-47; 1.19 (95% CI 0.35-4.10) for BDE-99; 0.91 (95% CI 0.33-2.53) for BDE-100; 0.52 (95% CI 0.19-1.39) for BDE-153; 1.67 (95% CI 0.44-6.29) for BDE-154; 2.04 (95% CI 0.45-9.20) for total BDEs. These results provide no evidence of an association between PBDE adipose concentrations measured at or near the time of diagnosis and breast cancer risk. Our study was limited by a small sample size. Given the high levels of PBDEs found in this population of California women, future studies are warranted. Such studies would benefit from a larger sample size, a more representative control series, and/or a prospective design.