Age-dependent alteration of antioxidant defense system in hypertensive and type-2 diabetes patients

BACKGROUND The association between hypertension and diabetes has been linked to increased oxidative stress with age. This study was to examine the level of age-dependent alterations in antioxidant defense system between patients having hypertension and/or type-2 diabetes. METHODS The study was conducted at the Ahmadu Bello University Teaching Hospital, Zaria-Nigeria, using 200 Subjects recruited from the cardiology, endocrinology and outpatient clinics. They were divided into four groups of 50 subjects each, namely: Diabetic group (DG), hypertensive (HG) and hypertensive-diabetic group (HDG) as cases. The control group (CG) was non-diabetic normotensive subjects. They were all stratified into six age-ranges namely 20-29, 30-39, 40-49, 50-59, 60-69, 70-79 years. Oxidative stress markers (lipid peroxidation, antioxidant vitamins and elements, enzymatic and non-enzymatic antioxidant) were measured in the blood sample collected from all subjects in each age group within the study groups. RESULTS The results in the DG, HG and HDG, showed that the percentage decrease in enzymatic antioxidants and antioxidant vitamins with age were significantly (P < 0.05) higher than 10.8% and 20.0% respectively when compared to the CG, whereas, the level of decrease in serum Selenium at same age range was significantly higher than 52.8%. The level of lipid peroxidation in the cases was observed to be significantly (P < 0.05) higher than 89.9% when compared to the mean reference values (2.94 ± 0.05 nmol/ml) of the CG at same age range. Also, the decrease levels of endogenous antioxidants were observed to be directly related to aging. CONCLUSION The result obtained demonstrates the percentage age-dependent alteration in oxidative stress markers. The percentage decrease in the antioxidant levels during aging could be an explanation to the possible link, underlying the complication of type-2 diabetes and hypertension in this locale. Hence, antioxidants supplements may be useful in the management of the diseases during aging.