ENVIRONMENTAL PCB AND PESTICIDE EXPOSURE AND RISK OF ENDOMETRIOSIS

Abstract

Endometriosis is an estrogen dependent gynecologic disorder affecting approximately 10% of females of reproductive age. Its etiology remains elusive though hormonal and immunological factors have been postulated as underlying mechanisms. Of late, there is increasing speculation that hormonally active environmental agents may be associated with endometriosis. We investigated 61 polychlorinated biphenyl (PCBs) congeners and 7 pesticides (i.e., mirex, hexachlorobenzene (HCB), b-BHC, Oxychlordane, trans-nonachlor (t-Nonachlor), Aldrin, and 1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene (p,p-DDE)) in relation to risk of incident endometriosis among women undergoing laparoscopy for either diagnostic or sterilization purposes, 1998–1999. Among the 100 eligible women identified, 84 agreed to be interviewed prior to laparoscopy. Blood specimens were collected from 80 (95%) consenting women. Thirty-two women had visually confirmed endometriosis while 52 did not. Among women with endometriosis, severity ranged from AFS-R Stage 1 (minimal, n = 15), Stage II (mild, n = 5). Stage III (moderate, n = 6), and Stage IV (severe, n = 6). All bloods were analyzed using gas chromatography with electron-capture. PCB congeners and pesticides were run in batches of 14 including four quality control samples (i.e., reagent control, serum control, control with 15 calibration standards at known values, and a duplicate participant sample). Congeners were calculated from standard curves for the 15 calibration standards, and the remaining congeners from response factors that were laboratory generated. Each congener and pesticide was adjusted for percent recovery and lipids; batch specific reagent blanks were subtracted as well. All PCB concentrations were expressed as ng/g serum lipid and summed into a total PCB concentration. Women with moderate/severe (Stages III and IV) endometriosis had a significantly higher mean concentration of total PCBs than women without disease (1.45 and 1.20 ng/g, respectively). No significant difference in mean PCB concentration was observed between women with mild/moderate (Stages I and II) and women without disease (1.44 and 1.20 ng/g, respectively). An elevated risk of endometriosis was observed for log of lipid adjusted total PCBs (OR = 1.98; 95% CI = 0.84,4.65) but not for DDE (OR = 0.93; 95% CI = 0.50,1.77) after controlling for household income, current cigarette smoking and parity. Risk of endometriosis remained for total PCBs after adjusting for DDE (OR = 2.13; 95% CI = 0.88,5.17). These data are suggestive of a possible association between PCBs and, possibly, more severe endometriosis but await confirmation in larger populations.