Purpose: We examined the association between endometriosis and exposure to polybrominated biphenyls (PBBs) and polychlorinated biphenyls (PCBs) among women inadvertently exposed to PBBs in 1973.
Methods: Serum PBBs and PCBs were measured in the late 1970s. Women self-reported endometriosis at interview in 1997. We constructed Cox models to estimate the relative incidence of endometriosis in relation to PBB and PCB levels.
Results: Seventy-nine of 943 women (9%) reported endometriosis. Compared with women with low PBB exposure (<or=1 parts per billion [ppb]), women with moderate PBB (1-4 ppb) (hazard ratio [HR] = 0.72; 95% confidence interval [CI], 0.39-1.31) and high PBB (>or=4 ppb) (HR = 0.90; 95% CI, 0.51-1.59) exposure did not have increased incidence of endometriosis. Increased incidence of endometriosis was suggested among women exposed to moderate PCB (5-8 ppb) (HR = 1.67; 95% CI, 0.91-3.10) and high PCB (>or=8 ppb) (HR = 1.68; 95% CI, 0.95-2.98) levels compared with low PCB exposure (<or=5 ppb).
Conclusions: Our study does not support an association between PBB exposure and endometriosis. Findings for serum PCB level are consistent with an emerging body of literature suggesting an association between PCB exposure and endometriosis.