Effect of Fat Loss on Arterial Elasticity in Obese Adolescents With Clinical Insulin Resistance: RESIST Study

CONTEXT: Reduced arterial elasticity contributes to an obesity-related increase in cardiovascular risk in adults. OBJECTIVE: To evaluate the effect of fat loss on arterial elasticity in obese adolescents at risk of type 2 diabetes. DESIGN: A secondary data analysis of the RESIST study was performed in two hospitals in Sydney, Australia. PARTICIPANTS: The study included 56 subjects (ages, 10 to 17 y; 25 males) with prediabetes and/or clinical features of insulin resistance. INTERVENTION: A 12-month lifestyle plus metformin intervention. OUTCOMES: Arterial elasticity and systemic vascular resistance were measured using radial tonometry pulse contour analysis, percentage body fat (%BF) was measured by dual-energy x-ray absorptiometry, and insulin sensitivity index was derived from an oral glucose tolerance test and lipids. RESULTS: Adolescents (n = 31) with decreased %BF (mean change [range], -4.4% [-18.3 to -0.01%]) after the intervention had significant increases in the mean large arterial elasticity index (mean change [95%CI], 5.1 [1.9 to 8.2] mL/mm Hg * 10; P = .003) and insulin sensitivity index (0.5 [0.1 to 0.9]; P = .010) and a decrease in systemic vascular resistance (-82 [-129 to -35] dyne * s * cm(-5); P = .001). There were no significant changes in these parameters in adolescents who increased their %BF. Nor was there any significant change in the mean small arterial elasticity index in either group. CONCLUSION: Long-term follow-up of these adolescents is warranted to assess whether the observed changes in vascular elasticity will lead to a clinical benefit including reduced cardiovascular morbidity and mortality.