Relationship Between Physical Activity and Vascular Function: Adolescent Obesity and Type 2 Diabetes

Abstract

PURPOSE: Childhood overweight and obesity have nearly tripled over the last 30 years, likely related to poor diet and decreased physical activity (PA). Several reports suggest that as a result of this phenomenon, cardiovascular (CV) risk factors and CV diseases (CVD) are beginning to present at much earlier ages. Arterial stiffness has been shown to be associated with obesity and CVD in adults, however very little information exists regarding adolescents and the role of PA in vascular function. Therefore, the T2CVD study was designed to determine the extent of the relationship between a non-invasive measure of arterial stiffness, aorto-femoral pulse wave velocity (PWV), and an objective measure of PA in a large sample of adolescents who are either normal weight (N), obese (O), or obese with Type 2 diabetes mellitus (T). METHODS: 258 subjects (age 14-23 yrs) 39% male, 65% non-Caucasian underwent anthropometric, dietary, PA, metabolic, and CV evaluation. PA was assessed by accelerometry (7 consecutive days during awake hours). PWV was measured using arterial tonometery. General Linear Models analyses were performed to evaluate group mean differences and elucidate independent determinants of vascular outcomes. RESULTS: Groups did not differ by age. T had the highest glucose and O & T had higher insulin than N. O had the lowest PA of all 3 groups. There was a graded increase in PWV from N to O to T (p<.0001) indicating increased stiffness. PWV was negatively correlated with PA (p<0.0002). Multivariate models demonstrated that PA was a significant independent negative determinate of arterial stiffness; other contributing factors are BMI Z-score, group (N,O,T), and race (R2 =0.33, p<0.001). CONCLUSIONS: Decreased PA is associated with increased arterial stiffness in adolescents with obesity and type 2 diabetes. Interventions to increase physical activity are needed to prevent early onset CV diseases in youth.