Environmental Polychlorinated Biphenyl Exposure and Risk of Endometriosis

Abstract

There is mounting evidence that endometriosis may have an environmental origin, possibly exposure to hormonally active agents such as dioxin and other compounds that bioaccumulate. Among candidate materials are polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs). Both animal and human studies support a role for PCBs and the development of endometriosis, an estrogen-dependent disorder. The present study examined the relationship, if any, between endometriosis and 62 individual PCBs. Eighty-four women 18 to 40 yeas of age who were scheduled for laparoscopy constituted the study group. Most were white, married, college-educated women; their mean age was approximately 32 years. Endometriosis was visually confirmed in 32 women. Women with endometriosis had fewer pregnancies and live births than did their unaffected peers. Both women with and those without endometriosis had relatively low serum concentrations of PCBs. Total serum PCBs ranged from 0.5 to 5.3 ng/g in women with endometriosis and from 0.2 to 5.6 ng/g serum for those without endometriosis. The sum of estrogenic PCB congeners ranged from 0.07 to 0.9 and from 0.4 to 1.7 ng/g serum, respectively. The respective figures for antiestrogenic congeners were 0.01 to 0.2 and from zero to 0.3 ng/g serum. On logistic regression analysis, a significantly elevated odds ratio for endometriosis of 3.8 was noted in women in the third tertile of antiestrogenic PCBs (95% confidence interval [CI], 1.1-12.7). The association remained significant at 3.3 (95% CI, 0.9-12.5) after controlling for gravidity, current cigarette smoking, and serum lipids. Gravidity and cigarette smoking were both associated with a significantly reduced risk of endometriosis. These findings suggest an association between antiestrogenic PCBs and the development of endometriosis.