Background & objective: Endometriosis is one of the most commonly encountered benign problems in gynaecology. It is frequently associated with chronic pelvic pain, dysmenorrhoea, menorrhagia and dyspareunia, which lead to infertility. To determine the possible association between polychlorinated biphenyls (PCBs) and GSTM1 null (*0/*0) mutation and their possible impact in the pathogenesis of endometriosis.
Methods: Ninety seven women with endometriosis mean age (28.5 +/- 6.5 yr) diagnosed by laparoscopy and 102 women without endometriosis (28.4 +/- 4.8 yr) were included. Heparinised blood samples were collected from all for DNA isolation and estimation of PCBs. GSTM1 genotyping was done by PCR and PCBs were estimated by gas chromatography.
Results: Women with endometriosis showed significantly higher concentrations of PCBs compared with control group. Twenty six (26.8%) women with endometriosis and 15 (14.7%) of the controls had the GSTM1 null (*0/*0) genotype [odds ratio (OR = 2.12, 95% confidence interval (CI) = 1.045-4.314], which showed significant association (P = 0.03) with endometriosis. The association between the concentrations of PCBs, GSTM1 null genotype and different severity of endometriosis was significant (P<0.05) for all four compounds and GSTM1 (PCB1: r = +0.5388, P<0.0001; PCB5: r = +0.6753, P<0.0001; PCB29: r = +0.6471, P<0.0001; and PCB98: r = +0.4357, P<0.0001; GSTM1: r = +0.9439, P = 0.05).
Interpretation & conclusion: The study results suggested that women having higher concentration of PCBs and GSTM1 null (*0/*0) polymorphism might have an increased susceptibility of endometriosis. The findings need to be confirmed in a larger sample.