Effects of Diet and Exercise on Obesity-Related Vascular Dysfunction in Children

BACKGROUND: The prevalence of obesity in both adults and children is increasing rapidly. Obesity in children is independently associated with arterial endothelial dysfunction and wall thickening, key early events in atherogenesis that precede plaque formation. METHODS AND RESULTS: To evaluate the reversibility of obesity-related arterial dysfunction and carotid intima-media thickening by dietary and/or exercise intervention programs, 82 overweight children (body mass index, 25+/-3), 9 to 12 years of age, were randomly assigned to dietary modification only or diet plus a supervised structured exercise program for 6 weeks and subsequently for 1 year. The prospectively defined primary end points were ultrasound-derived arterial endothelial function (endothelium-dependent dilation) of the brachial artery and intima-media thickness of common carotid artery. At 6 weeks, both interventions were associated with decreased waist-hip ratio (P<0.02) and cholesterol level (P<0.05) as well as improved arterial endothelial function. Diet and exercise together were associated with a significantly greater improvement in endothelial function than diet alone (P=0.01). At 1 year, there was significantly less thickening of the carotid wall (P<0.001) as well as persistent improvements in body fat content and lipid profiles in the group continuing an exercise program. Vascular function was significantly better in those children continuing exercise (n=22) compared with children who withdrew from the exercise program (n=19) (P<0.05). CONCLUSIONS: Obesity-related vascular dysfunction in otherwise healthy young children is partially reversible with diet alone or particularly diet combined with exercise training at 6 weeks, with sustained improvements at 1 year in those persisting with diet plus regular exercise.