This study aimed to investigate the effects of blood lead levels (BLLs) and lead and cadmium exposure on endometriosis (EM). The study cohort consisted of female workers who underwent a lead-associated special medical examination between 1 January 2000 and 31 December 2004 (n = 26,542). The standard admission rate (SAR) and admission odds ratio (OR) for EM were calculated using the general population and noise-exposed groups, respectively, for the same period as the reference standards. The SAR for EM was 1.24 (95% confidence interval (CI): 1.03-1.48) in lead-exposed workers and 1.44 (95% CI: 1.11-1.85) in workers with BLLs < 5 μg/dL when compared with that of the general population. Admission ORs of EM in lead-exposed workers and those with BLLs < 5 μg/dL were statistically higher than those of noise-exposed workers (OR, 1.40; 95% CI, 1.15-1.70 and OR, 1.48; 95% CI, 1.11-1.98, respectively). The relative excess risk due to interaction of lead and cadmium was 0.33. Lead exposure was associated with EM admission. EM admission in lead-exposed workers with BLLs < 5 μg/dL was statistically higher than that of the general population and noise-exposed workers. Co-exposure to lead and cadmium has a synergistic effect with EM.
Keywords: cadmium; endometriosis; lead; synergic effect.