Evidence for augmented oxidative stress in the subjects with type 1 diabetes and their siblings: a possible preventive role for antioxidants

BACKGROUND/OBJECTIVES: Oxidative stress (OS) is thought to be involved in both development of type 1 diabetes (T1D) and its further complications. In this study, certain biomarkers of OS were compared among the subjects with T1D, their non-diabetic siblings and unrelated healthy controls. SUBJECTS/METHODS: Known cases of T1D from both sexes aged 5–25 years were enrolled in a case–control study ( n 1 =60). There were two control groups; non-diabetic siblings ( n 2 =60) and unrelated apparently healthy subjects ( n 3 =60). Anthropometric, dietary and laboratory assessments were done. RESULTS: There was no significant difference in dietary data among the groups. Total antioxidant capacity was significantly lower in T1D than both related and unrelated controls (1.6±0.05, 1.7±0.05 and 1.8±0.06 mmol BSA equivalent/l, respectively, P =0.044). Both T1D subjects and their siblings showed lower glutathione peroxidase (GSH-px) levels (median (interquartile range): 22.2 (28.6), 29.9 (23) and 41.8 (73.6) U/ml, respectively, P =0.006). On the contrary, superoxide dismutase concentrations were significantly higher in T1D group and the siblings than unrelated healthy controls (243 (45.3), 157.8 (176.9) and 27.9 (8.7) U/l, respectively, P