ardiometabolic risk factors associated with the development of insulin resistance (IR), such as obesity, hypertension, and dyslipidemia, promote the development of atherosclerosis. These cardiovascular risk factors not only are evident in youth, but also are known to track into adulthood. Unfortunately, risk factor-related vascular changes are occurring early in life, as seen in data from autopsies performed on participants in the Bogalusa Heart Study, where adverse values of body mass index (BMI), blood pressure (BP), smoking, and serum cholesterol-specifically total, low-density lipoprotein, and high-density lipoprotein cholesterol-were associated with coronary and aortic fatty streaks in subjects aged 2-39 years. 1 Similar findings (other than an association with low-density lipoprotein cholesterol) were seen in the Pathobiological Determinants of Atherosclerosis in Youth (PDAY) autopsy study. 2 Recent studies in youth have used noninvasive testing to demonstrate early atherosclerosis. These studies have used various modalities to differentiate "normal" and "accelerated" vascular aging by demonstrating adverse changes in the arteries in high-risk youth. In a recent article published in The Journal, Hughan et al 3 compared pulse wave velocity (PWV), a measure of arterial stiffness, and carotid intima-media thickness (cIMT), reflecting atherosclerosis, and endothelial function biomarkers among girls with obesity with and without polycystic ovary syndrome (PCOS) and healthy, normal-weight girls in a crosssectional fashion. 3 They found significantly stiffer arteries (ie, increased PWV) in the obese youth with or without PCOS compared with controls, even when adjusted for age, race, and BP (P = .002). There was no difference in cIMT among the 3 groups; however, there were differences in endothelial biomarkers, specifically VCAM-1 (P = .03). In addition, correlations between PWV and traditional cardiovascular (CV) risk factors demonstrated that PWV had the closest correlation with BMI. The authors concluded that obesity is the more important factor leading to abnormalities in vascular function in PCOS. In this review, we discuss the available evidence linking obesity-related CV risk factors in youth and the noninvasive measures of vascular structure and function.