[Active Substance Index (AKS) percentile distribution in pediatric ages].

The aim of this study was to discern the percentile distribution of the Active Substance Index (AKS) in boys and girls aged 4 to 9 years in order to obtain reference values for this indicator. This index was calculated in 3634 healthy and well-nourished children with normal stature from a poor urban community at Centro de Atención Nutricional Infantil Antímano (CANIA), within the period between January 1999 and December 2007. Children with prematurity backgrounds, pubertal growth spurts, or with chronic pathologies, whether defined or under study, were excluded. The Dugdale & Griffiths two-skinfold equation for boys and girls shorter than 150 cm and 140 cm, respectively was used to obtain the fat body mass required to estimate the AKS index. The variables were measured by standardized anthropometrics technicians, with quality control every 4 months as recommended by international standards. Descriptive statistics of the AKS index and variables used for their calculation were obtained, as well as index percentiles 3, 10, 25, 50, 75, 90, and 97. Tests applied included Kolmogorov-Smirnoff, Anova one-way, Chi Square, Tukey and bivariated correlations (p < 0.05). The AKS index behavior exhibited higher values in the boys, decreasing with age in both sexes, ranging from 1.28 to 1.04 in the boys and from 1.17 to 0.94 in the girls. Statistically significant differences were found for each age and sex. These results provide the AKS index percentile distribution values needed for nutritional assessments in pediatric ages. These values should be validated and their effectiveness should be studied.