Purpose: Concerns regarding a possible link between bisphenol A (BPA) and breast cancer have been mounting, but studies in human populations are lacking. We evaluated the association between the major urinary BPA metabolite [BPA-glucuronide (BPA-G)] and postmenopausal breast cancer risk in a large population-based case-control study conducted in two cities in Poland (2000-2003); we further explored the association of BPA-G levels with known postmenopausal breast cancer risk factors in our control population.
Methods: We analyzed creatinine-adjusted urinary BPA-G levels among 575 postmenopausal cases matched on age and study site to 575 controls without breast cancer using a recently developed assay. Odds ratios and 95 % confidence intervals were used to estimate the association between urinary BPA-G level and breast cancer using conditional logistic regression. Among controls, geometric mean BPA-G levels were compared across categories of breast cancer risk factors using linear regression models.
Results: There was no indication that increased BPA-G was associated with postmenopausal breast cancer (p-trend = 0.59). Among controls, mean BPA-G was higher among women reporting extended use of menopausal hormones, a prior screening mammogram, and residence in Warsaw. Other comparisons across strata of postmenopausal breast cancer risk factors were not related to differences in BPA-G.
Conclusions: Urinary BPA-G, measured at the time of diagnosis, is not linked to postmenopausal breast cancer.