Insulinemia e índice HOMA en niños y adolescentes chilenos.
NORMAL PLASMA INSULIN AND HOMA VALUES AMONG CHILEAN CHILDREN AND ADOLESCENTS
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 old, 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. Anthropometry 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). Women had higher insulin and HOMA values than men (12.5±6.0 and 9.1±4.9 ?U/mL (p< 0.01) and 2.7±1.4 and 2.1±1,1 (p< 0.01), respectively). Subjects with Tanner I and 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 µU/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 males was 3.2, for Tanner I and II women was 4.1, for Tanner III and IV men was 4.2 and for Tanner III and IV women was 5.0.