POOR GLYCEMIC CONTROL IS ASSOCIATED WITH REDUCED SERUM-FREE RADICAL SCAVENGING (ANTIOXIDANT) ACTIVITY IN NON-INSULIN-DEPENDENT DIABETES-MELLITUS

The diabetic patient is at significantly increased risk of developing vascular disease, its aetiology may involve oxidative damage by free r adicals and protection against such damage can be offered by radical-s cavenging antioxidants. We investigated whether there was a relationsh ip between glycaemic control as assessed by measurement of glycated ha emoglobin (HbA(1c)) and serum antioxidant status in a population of 11 8 diabetic outpatients with either insulin-dependent or non-insulin-de pendent diabetes. Amongst patients with non-insulin-dependent diabetes mellitus there was a significant inverse correlation between levels o f glycated haemoglobin and total free radical scavenging activity (r = -0.456, P<0.0001). This association resulted primarily because of a s imilar correlation with uric acid (r = -0.421, P=0.0003). There was al so a weak inverse correlation with vitamin A bur no significant associ ation with vitamin C or vitamin E levels, There were no significant as sociations found amongst the patients with insulin-dependent diabetes, These results indicate that poor diabetic control is associated with reduced serum free radical scavenging (antioxidant) activity in non-in sulin-dependent diabetes mellitus. By implication improved glycaemic c ontrol may preserve serum antioxidant status in diabetes.