Bioelectrical impedance values among indigenous children and adolescents in Rio Grande do Sul, Brazil.

OBJECTIVE To describe the nutritional status of indigenous children and adolescents in Rio Grande do Sul, Brazil, through bioelectrical values, and to compare the nutritional classifications of the anthropometric method to those of the body composition method. METHODS A cross-sectional survey was conducted of 3 204 subjects at 35 schools in the 12 Kaingang indigenous lands of Rio Grande do Sul, Brazil. Following World Health Organization recommendations, the weight and height (H) of each subject was measured twice and the body mass index/age (BMI/A) was classified. Body composition was assessed by Bioelectrical Impedance Vector Analysis (BIVA). Resistance (R) and reactance (Xc) were estimated using a bioelectrical impedance analyzer. Divergences between these two methods were performed on RXc graph. RESULTS Of the sample, 56.8% were adolescents and 50.6% were males. The mean values of phase angle were higher in adolescents, in males, and in individuals overweight by BMI/A. Mean values of R, Xc, R/H, and Xc/H were higher among children and among those with BMI/A < +2 z scores. Divergences in overweight classification were: male children, 94.6%; male adolescents, 77.1%; female children, 85.4%; and female adolescents, 94.8%. CONCLUSIONS The mean values of bioelectrical measures observed among the Kaingang children and adolescent were similar to those found for different populations in other studies. For both gender and age groups, differences were observed between nutritional classifications by BMI/age and by BIVA. These results reinforce the importance of employing multiple techniques, such as anthropometry and BIVA, when conducting nutritional assessments of a population.