CAT and diabetes mellitus: In this study, the level of serum lipid peroxidation (Malondialdehyde: MDA), serum antioxidants (reduced glutathione: GSH, superoxide dismutase: SOD, catalase: CAT), antioxidant vitamins (Vitamins C and E) and some serum antioxidant elements (zinc: Zn, copper: Cu, selenium: Se, and iron: Fe) in patients with diabetes, hypertension and both hypertension/diabetes at various age range was investigated along with that of healthy adults at same age range in order to ascertain the effect of age changes on the antioxidant.