Association between heavy metals and endometriosis

Abstract

OBJECTIVE: To determine the association between heavy metal concentrations in whole blood and ectopic endometrial tissue in endometriosis. METHODS: A case-control study was conducted in a tertiary care hospital. Endometriosis was confirmed by laparoscopy or laparotomy in 14 patients, There were 11 age-matched controls with no evidence of the disease. Informed written consent was obtained pre-operatively. Blood samples were collected from all participants. In 10 patients ectopic endometrial tissue samples were obtained by a single surgeon. After measuring the wet weight, whole blood samples and ectopic endometrial tissues were digested with supra pure 65% HNO3 and analysed for heavy metals by the Total Reflection X-ray Fluorescence (TXRJF) technique in parts per billion (PPB). Means of the log transformed metal levels were compared using t-tests. RESULTS: Mean (+SD) blood levels of nickel in the cases (2.19±0.45 PPB) was significantly higher than in the controls (0.65±0.14 PPB, p =0.029). The mean (+SD) lead levels in the cases (21.85±1.99 PPB) and controls (17.85 ±1.5 PPB) were similar (p=0.378). Tissue samples had higher mean (+SD) levels of nickel (9.3±15.31 PPB) and lead (66.60±10.37 PPB) as compared to blood levels of nickel (0.502±0.406 PPB) and lead (18.16 ± 1.58 PPB) which were statistically significant (p=0.003 and p=0.025 respectively). CONCLUSIONS: Patients with endometriosis had higher levels of nickel, which is known to exert oestrogenic effects. There is evidence that nickel accumulates in endometrial tissues.