Total antioxidant status and coronary artery calcification in type 1 diabetes

OBJECTIVE - Type I diabetes is associated with a high risk of coronary hear t disease (CHD). despite the absence of dyslipidemia. Oxidative modificatio n may render LDLs more atherogenic. We aimed to assess antioxidant status i n type I diabetes and its association with coronary artery calcification (C AC). RESEARCH DESIGN AND METHODS - Total antioxidant status (TAS) of serum was m easured using the Trolox equivalent antioxidant capacity assay in 48 type I diabetic and 25 nondiabetic subjects, The presence of CAC was assessed in the diabetic subjects using electron beam computed tomography. RESULTS - TAS was reduced in type 1 diabetic subjects compared with nondiab etic subjects (Mann-Whitney U test, P < 0.0001). There were associations be tween TAS and HbA(1c) (r = 0.43: P = 0.0026) and duration of diabetes (r = -0.35; P = 0.0157). Significant CAC was considered present if the Agatston score was > 10. The diabetic subjects with significant CAC were older (P < 0,0001) had longer duration of diabetes (P = 0.0002); were more likely to h ave high blood pressure (P = 0.040); had higher total cholesterol concentra tion (P = 0.039), serum creatinine concentration (P = 0.003), and urinary a lbumin-to-creatinine ratio (P = 0.022); and cre had lower serum TAS (P = 0. 018) compared with these without significant calcification. In logistic reg ression with CAC as the dependent variable, TAS was entered as a predictor, and the effects on its predictive value of adding other explanatory variab les in bivariate analyses were assessed. The power of TAS to predict CAC wa s independent of many of the traditional CHD risk factors. Whereas TAS as a predictor was no longer statistically significant when age or duration - o f diabetes were entered into the model, the odds ratio fora TAS concentrati on above the median value predicting significant CAC only increased from 0. 19 to 0.26 and 0.32, respectively. CONCLUSIONS - TAS is reduced in type 1 diabetes and is associated with the presence of CAC.