[The HOMA and QUICKI indexes, and insulin and C-peptide levels in healthy children. Cut off points to identify metabolic syndrome in healthy children].

OBJECTIVE: The aim of this study was to establish the reference values of the Homeostasis Model Assessment (HOMA) and Quantitative Insulin Sensitivity Check (QUICKI) indexes, as well as those of insulin and C-peptide levels in healthy children and adolescents with a view to determining reference percentiles to detect those at cardiovascular risk.
MATERIAL AND METHODS: A total of 372 children boys and girls of different ages and at distinct pubertal stages with normal body mass index participated in the study. Fasting glucose, insulin and C-peptide values were measured by chemiluminescence and the HOMA and QUICKI indexes were calculated.
RESULTS: Fasting glucose levels were normal in all children. The mean values obtained for each variable were (mean (SD)): fasting glucose 87(7.75) mg/dL, insulin 7.74 (5.35) microU/mL, C-peptide: 1.76 (0.79) ng/mL, HOMA index 1.72 (1.27) and QUICKI index 0.72 (0.29). All the variables progressively increased with age, with statistically significant differences between prepubertal and pubertal children. The QUICKI index showed an inverse relationship. In addition, significant differences were found between sexes. The 90th percentile for all the variables was as follows: insulin 15.05 microU/mL, C-peptide: 2.85 ng/mL, HOMA index 3.43 and QUICKI index 1.10.
CONCLUSIONS: Values of fasting glucose, insulin, C-peptide and the HOMA index significantly increased with age and pubertal stage, while the QUICKI index decreased. We defined the 90th percentile for all the parameters studied as the cut-off point to identify children at cardiovascular risk in our population.