Insulin level and insulin sensitivity indices among healthy children and adolescents.

INTRODUCTION Information on insulin reference values and insulin sensitivity indices in the field of pediatrics is scarce. OBJECTIVE To describe insulin range and insulin sensitivity surrogate indices during childhood. MATERIALS AND METHODS Fasting insulin level range and surrogate indices, such as the homeostasis model assessment of insulin resistance (HOMA-IR), among healthy children and adolescents by age, body mass index, pubertal stage (PS), insulin-like growth factor-1 (IGF-1), total cholesterol, and triglycerides. RESULTS Two hundred and twenty-six healthy children and adolescents (1-18 years old) were included. Insulin increased with age, body mass index, pubertal stage, IGF-1 and triglyceride levels (r2= 0.38, p 〈 0.0001). Prepubertal children 〉 7.5 years old had higher insulin levels [median (P3 and P97) pIU/mL: 5.0 (1.7-9.6)] than prepubertal children 〈 7.5 years old [2.9 pIU/ mL (1.3-10.9), p 〈 0.01]. During puberty (from PS II to PS V), insulin was higher in girls than in boys [7.4 (1.8-16.9) versus 5.8 (1.8-12.9), p 〈 0.01]. The HOMA-IR index increased in the group of prepubertal children 〉 7.5 years old: 1.1 (0.32.0) versus children 〈 7.5 years old: 0.6 (0.3-1.4, p 〈 0.01). The insulin level and HOMA-IR results were higher in pubertal children compared to the prepubertal group (p 〈 0.001). CONCLUSIONS Known physiological changes were observed inboth insulin levels and the HOMA-IR index among children and adolescents. A fasting blood insulin level of 10 pIU/mL in prepubertal children and of 17 pIU/mL and 13 pIU/mL in pubertal girls and boys, respectively, may be considered as an acceptable cut-off value in healthy children. A HOMA-IR value 〉 2.0 and 〉 2.6 in prepubertal and pubertal children, respectively, may be considered a warning sign for pediatricians to further investigate insulin resistance.