MPO and juvenile idiopathic arthritis: Mean IMT (0.46 ± 0.04 vs. 0.42 ± 0.04 mm; p = 0.0003) and MPO concentration (115.2 [95 % confidence interval {95 % CI}, 97.4–136.3] vs. 57.6 [95 % CI, 47.1–70.3] ng/ml; p < 0.0001) were higher in the patients with JIA than in the control subjects.