Study of The Role of Mercury Poisoning in Rheumatoid Arthritis Patients and Its Relation with Zinc and Copper Levels

Abstract

The present study aimed to evaluate role of increased blood levels of mercury on rheumatoid arthritis patients in Dakahlia governorate and to investigate the correlation between levels of zinc and copper in the blood with that of mercury and their relation to the disease activity. The present study included 32 patients (test group) suffering from rheumatoid arthritis (RA) attending the rheumatology and rehabilitation out patient clinic, Mansoura university hospital and 30 healthy volunteers (control group) matched according to age, sex, residence and occupation. All patients of the test group were evaluated by Disease Activity Score (DAS 28) and accordingly, the test group included 10 patients (31.3%) with mild to moderate DAS and 22 patients (68.7 %) with high DAS (6 patients were with dental filling amalgam and 16 were free from amalgam). Blood mercury, zinc and copper levels were determined using atomic absorption spectrophotometer. The present study observed significant increase in blood mercury levels while, blood zinc and copper levels were significantly decreased in the test group when compared to the control group. As regards the presence of dental amalgam, the present results revealed that the highest mercury levels (mean +SD was 13.13 ± 0.58 ∝ g/dl), the lowest zinc levels (mean +SD was 108.28 ± 7.89 ∝ g/dl) and relatively the lowest copper levels (mean +SD was 7.26 ± 0.73 ∝ g/dl) were observed in severe RA activity score patients with dental filling amalgam. There were a significant negative correlation between blood mercury and zinc levels and DAS while, there was non-significant negative correlation was found between blood copper levels and DAS. In conclusion, the current study provided some support for the hypothesis that dietary intake or inhalation of toxic elements (mercury), most probably through dental filling amalgam, may increase the risk of rheumatoid arthritis.