Homocysteine, oxidative stress and depression among patients with type 2 diabetes mellitus

Abstract

Oxidative stress was recently involved in the pathogenesis of type 2 diabetes. In this case‐control study we measured homocyseteine (HCY), vitamin B12 and folate as well as oxidative stress markers [glutathione (GSH), total antioxidant capacity (TAC) and antioxidant enzymes (GPX, glutathione peroxidase, SOD, superoxide dismutase and CAT, catalase)], in the sera of type 2 diabetic Omani patients. One hundred subjects (50 patients and 50 controls) were recruited for this study. Depression and anxiety were assessed for all study participants. Dietary folate and vitamin B12 intake of cases were lower than controls and the recommended dietary allowances (RDA). Depression and anxiety were higher among cases as compared to controls. The mean serum HCY was higher in cases as compared to normal values of serum HCY. Cases have low levels of GSH, TAC, GPX, SOD and CAT as compared to controls. Depression and anxiety were significantly correlated with low levels of dietary and serum folate and vitamin B12. The findings of this study indicate that, among the studied type 2 diabetic Omani subjects, the pathogenesis of depression and anxiety were attributed to (1) high serum level of HCY, (2) low levels of dietary and serum folate and vitamin B12, and (3) oxidative stress as indicated by low levels of GSH, TAC and antioxidant enzymes.