Measures of Cardiovascular Health in Obese Youth

by Neal, Ashley

Among numerous other comorbidities, evidence continues to emerge supporting a relationship between childhood overweight and traditional markers of cardiovascular risk in adults. The ultimate ramifications of this association in terms of cardiovascular morbidity and mortality have not yet been fully elucidated. This thesis seeks to evaluate markers of cardiovascular health in a cohort of otherwise healthy, obese adolescents. Baseline data was collected from 24 obese adolescents with normal glucose tolerance enrolled in a clinical trial of metformin therapy. In addition to anthropometric measurements, fasting levels of serum lipids and C-reactive protein were obtained and an oral glucose tolerance test was conducted. Peripheral arterial tonometry (PAT) testing, a novel, noninvasive approach for assessing endothelial dysfunction, was performed and heart rate recovery was measured following a selfpaced step test. Potential relationships between indices of metabolic control and measures of cardiovascular risk including endothelial dysfunction and poor heart rate recovery were considered. No significant relationship could be demonstrated between results of peripheral arterial tonometry testing and measures of metabolic control or between this index and any other marker of cardiovascular health. However, there was a general trend toward impaired endothelial function with increasing postprandial glycemia. Additionally, no significant relationships were found between heart rate recovery and indices of glucose tolerance, but there was a general trend toward reduced heart rate recovery with increasing insulin resistance. Further research may support a role for noninvasive modalities such as PAT testing and heart rate recovery in longitudinal, as opposed to baseline, assessment of cardiovascular health in obese adolescents.