Polybrominated Biphenyl Exposure and Benign Breast Disease in a Cohort of US Women,

PURPOSE: We examined the relation between serum polybrominated biphenyl (PBB) levels and the risk of benign breast disease in a cohort of Michigan women unintentionally exposed to PBBs in 1973 and interviewed in 1997. METHODS: We used extended Cox models to generate adjusted hazard ratios; models included polychlorinated biphenyls (PCBs) and risk factors for benign breast disease reported in the literature. RESULTS: Two hundred fourteen (23%) of 951 women reported benign breast disease diagnosed by a physician. Compared with women with low PBB exposure, benign breast disease was not reported more frequently among those with moderate (>1–12 parts per billion [ppb]), (odds ratio [OR] 1.08, 95% confidence interval [CI] = 0.80–1.45), or high (>12 ppb), (OR 0.79, 95% CI = 0.46–1.38) PBB exposure. PCB exposure was also not associated with self-reported physician-diagnosed benign breast disease. Age, smoking, and annual number of health-care provider visits were significantly associated with benign breast disease. CONCLUSIONS: Our analysis did not demonstrate an association between serum PBB level and self- reported physician-diagnosed benign breast disease. We did observe an increased risk of benign breast disease for women who smoked, an association that has not been consistently found in previous studies.