Normal plasma insulin and HOMA values among chilean children and adolescents

Abstract

Background: Plasma insulin and HOMA (homeostasis model assessment) index, used to determine insulin resistance, do not have local standard values for children and adolescents in Chile. Aim: To establish the normal reference intervals for insulin and HOMA in children and adolescents aged 10-15 years, according to sex and puberal maturation. Material and Methods: A cross-sectional study of 2,153 children and adolescents from Puente Alto County was performed, during 2009 and 2010. Anthropoinetry and self-report of puberal maturation were assessed. Fasting glucose (hexoquinase) and insulin blood levels (chemiluminiscence), were determined and HOMA index was calculated. Percentile distributions of these variables were calculated. Results: The reference group included only subjects with normal body mass index and fasting blood glucose (n = 1,192). Girls had higher insulin and HOMA values than boys (12.5 +/- 6.0 and 9.1 +/- 4.9 mu U/mL (p <0.01) and 2.7 +/- 1.4 and 2.1 +/- 1,1 (p <0.01), respectively). Subjects with Tanner land II puberal stages had lower insulin and HOMA mean values than subjects with Tanner III and IV (9.0 +/- 4.3 and 12.5 +/- 6.2 mu U/ml (p < 0.01) and 2.0 +/- 1 and 2.8 +/- 1.4 (p <0.01), respectively). Conclusions: The 90th percentile of insulin and HOMA distributions according to sex and maturation, was selected as the upper cut-off point to identify individuals with insulin resistance. HOMA cutoff point for Tanner I and II boys was 3.2, for Tanner land II girls was 4.1, for Tanner III and IV boys was 4.2 and for Tanner III and IV girls was 5.0. (Rev Med Chile 2011; 139: 1435-1443).