BACKGROUND Obesity in childhood is associated with an increased mortality due to cardiovascular (CV) diseases in adulthood, independent of adult weight. Recent studies in children indicate that the atherosclerosis process starts at an early age and is linked to obesity. OBJECTIVE The aim of the study was to investigate determinants of increased carotid intima-media thickness (IMT), an early marker of atherosclerosis, in obese children. METHODS A total of 104 obese children [age, 12.7 +/- 0.2 yr; body mass index (BMI)-z-score, 2.8 +/- 0.7] underwent an oral glucose tolerance test. Fasting levels of glucose, insulin, C-reactive protein and adhesion molecules (sICAM, sVCAM, sE-selectin), lipid profile, adiponectin, and resistin were determined. IMT was measured by ultrasound. Insulin resistance was estimated by the homeostatic model assessment index. Baseline measurements of blood parameters were obtained from 93 nonobese children (age, 13.0 +/- 0.2 yr; BMI-z-score, -0.2 +/- 0.9), and IMT was measured in 23 other control children with similar characteristics. RESULTS Univariate analysis showed a significant positive correlation between IMT and relative BMI, the degree of systolic hypertension, fasting insulin levels, homeostatic model assessment-R index, and resistin concentrations, whereas an inverse correlation with adiponectin levels was found. No correlation was obtained between IMT and classical CV risk factors such as positive familial history of type 2 diabetes or precocious CV disease, visceral obesity, or the lipid profile. C-reactive protein and adhesion molecule levels were not associated with IMT in our obese population. When controlled for sex, Tanner stage, and relative BMI, only adiponectin levels remained an independent determinant of IMT. CONCLUSIONS Adiponectin more than conventional CV risk factors and inflammation status may be related to early atherosclerosis in obese children.