Diabetes increases the risk of coronary heart disease (CHD) to a greater extent in women than in men. We investigated whether type 1 diabetic patients with short duration of disease and without complications have an altered oxidative status and whether there are differences between men and women. We investigated oxidative status in 29 control subjects and 37 patients with uncomplicated type 1 diabetes with duration of 6 +/- 3 years. Compared with control subjects, type 1 diabetic patients had lower total plasma antioxidant capacity (TRAP) (720.3 +/- 111.2 vs. 972.5 +/- 97.7 micromol/l in men, P < 0.001; 579.8 +/- 95.4 vs. 930.1 +/- 84.2 in women, P < 0.001), higher lipid hydroperoxide (ROOH) levels (6.4 +/- 2.2 vs. 2.0 +/- 0.7 micromol/l in men, P < 0.001; 8.1 +/- 1.9 vs. 2.2 +/- 0.6 in women, P < 0.001), higher total conjugated diene (CD) levels (0.037 +/- 0.003 vs. 0.033 +/- 0.002 A.U. in men, P < 0.001), lower 246-nm CD levels (0.0032. +/- 0.0010 vs. 0.0070 +/- 0.0012 A.U. in men, P < 0.001; 0.0022 +/- 0.0011 vs. 0.0072 +/- 0.0014 A.U. in women, P < 0.001), and higher 232-nm CD levels (0.0348 +/- 0.0041 vs. 0.0257 +/- 0.0022 A.U. in men, P < 0.001; 0.0346 +/- 0.0031 vs. 0.0246 +/- 0.0074 A.U. in women, P < 0.001). Compared with diabetic men, diabetic women had lower TRAP (P < 0.01), higher ROOH levels (P < 0.01), and lower 246-nm CD levels (P < 0.05). Plasma concentration of uric acid was significantly lower in patients with type 1 diabetes than in control subjects (3.3 +/- 0.3 vs. 4.3 +/- 0.2 mg/dl; P = 0.009) with a significant difference between women and men with type 1 diabetes (2.6 +/- 0.3 vs. 3.9 +/- 0.3, respectively; P = 0.009). Our findings suggest that reduced antioxidant activity and increased oxidative stress occur early after the diagnosis of type 1 diabetes, especially in women, and this might explain, at least in part, the increased susceptibility of diabetic women to cardiovascular complications.
