Relation of body mass index and insulin resistance to cardiovascular risk factors, inflammatory factors, and oxidative stress during adolescence

Background - This study assessed the relation of fatness and insulin resistance and their interaction with cardiovascular risk factors, inflammatory factors, and oxidative stress in thin and heavy adolescents. Methods and Results - Euglycemic insulin clamp studies were performed on 295 (169 male, 126 female) adolescents (mean±SE age, 15±0.1 years). Comparisons were made between (1) heavy and thin adolescents; (2) insulin-sensitive and insulin-resistant adolescents; and (3) thin insulin-sensitive (T-IS), thin insulin-resistant (T-IR), heavy insulin-sensitive (H-IS), and heavy insulin-resistant (H-IR) adolescents. Summed z scores were used to determine clustering of risk factors (fasting insulin, triglycerides, HDL-C, and systolic blood pressure [SBP]) among the groups. SBP, triglycerides, and fasting insulin were significantly higher and HDL-C significantly lower in the heavy adolescents. Fasting insulin and triglycerides were significantly higher and HDL-C significantly lower in the insulin-resistant adolescents. Among the 4 groups, the risk factors and cluster score followed a pattern of risk as follows: T-IS<T-IR<H-IS<H-IR, with H-IR significantly greater than the other groups and showing an interaction between fatness and insulin resistance. Conclusions - These results show the significant association of both fatness and insulin resistance and their significant interaction with cardiovascular risk factors in adolescence. The finding that insulin resistance may be acting interactively with fatness suggests that interventions directed at insulin resistance in addition to weight loss may be required to alter early development of cardiovascular risk.