Oxidative DNA Damage and Zinc Status in Patients With Rheumatoid Arthritis in Duhok, Iraq

Background In patients with rheumatoid arthritis, oxidative DNA damage is increased by deficient zinc levels as well as increasing disease activity. However, the relationship between zinc levels, disease activity, and oxidative DNA damage remains unclear. In this study, we investigated serum zinc levels and disease activity and their association with 8-hydroxy-2-deoxyguanosine (8-OHdG). Methodology This case-control study was conducted among rheumatoid arthritis patients (n = 264) and healthy individuals (n = 192). Oxidative DNA damage was assessed by measuring serum 8-OHdG using enzyme-linked immunosorbent assay. Colorimetry was used to measure serum zinc levels. Disease activity was assessed using the Disease Activity Score-28 (DAS-28) score. Results Significantly higher 8-OHdG levels (p < 0.00) were found in the test group compared to the control group. Moreover, significantly lower serum zinc levels (p < 0.001) were noted in patients with rheumatoid arthritis compared to the control group. In addition, higher 8-OHdG levels were found in patients with low serum zinc levels compared to those with normal mean serum zinc levels. Lower levels of DNA oxidative damage were found in patients with moderate and low disease activity compared to those with high disease activity. A significant negative correlation was noted between serum zinc levels and DAS-28 scores and oxidative DNA damage marker (r = - 0.30, p = 0.038 and r = - 0.26, p = 0.043, respectively), while a significant positive correlation was observed between body mass index and 8-OHdG (r = 0.22, p = 0.02) in healthy individuals. Conclusions High serum 8-OHdG levels and high disease activity with low mean serum zinc levels may indicate a high degree of oxidative DNA damage in patients with rheumatoid arthritis.