['Asymmetric dimethylarginine (ADMA) has recently emerged as an independent risk marker for cardiovascular disease, but studies investigating the ADMA levels in type 1 diabetes mellitus (DM) are scarce.', 'We aimed to evaluate plasma ADMA, L-arginine concentrations, and L-arginine to ADMA ratio in uncomplicated type 1 diabetic patients and controls.', 'Forty patients with type 1 DM who did not have clinical evidence of vascular complications and 35 healthy controls were included in the study.', 'Plasma ADMA concentrations were higher (2.6 +/- 1.9 vs. 1.7 +/- 0.7 micromol/liter, P < 0.01), and L-arginine levels were lower (79.3 +/- 22.6 vs. 89.6 +/- 19.4 micromol/liter, P < 0.05) in the diabetic group, compared with controls. The L-arginine to ADMA ratio was also lower in the diabetic group (38.7 +/- 17.1 vs. 62.0 +/- 27.9, P < 0.0001). In diabetic patients, logADMA correlated positively with body mass index (BMI) (P = 0.01), fasting blood glucose (P = 0.006), and low-density lipoprotein cholesterol (LDL-c) (P = 0.01) and negatively with high-density lipoprotein cholesterol (P = 0.03). L-arginine to ADMA ratio correlated negatively with BMI (P = 0.004), fasting blood glucose (P = 0.02), and LDL-c (P = 0.01) and positively with high-density lipoprotein cholesterol (P = 0.04). In controls, logADMA and L-arginine to ADMA ratio correlated with BMI and LDL-c (P < 0.05). In regression analysis, BMI predicted 15% variance of ADMA levels (P = 0.02).'] Is uncomplicated type 1 diabetes associated with increased asymmetric dimethylarginine concentrations?