Diagnosing the nutritional status of schoolchildren: a comparison between Brazilian and international criteria.

OBJECTIVE To compare Brazilian and international criteria for assessing the nutritional status of schoolchildren. METHODS This was a cross-sectional study that enrolled 160 schoolchildren from a public school in the city of Rio de Janeiro, 91 boys and 69 girls, aged 7 to 9 full years. Body mass index (BMI) for sex and age was used to diagnose underweight, healthy weight and overweight, according to Cole et al., Conde & Monteiro and the World Health Organization (WHO) criteria. Student's t test, the chi-square test, the Kendall concordance test and the chi-square test for tendencies were used to analyze the data; graphs were plotted demonstrating BMI by age, according to the nutritional diagnosis at each set of criteria. RESULTS Mean BMI did not differ by sex (t = 0.2845, p = 0.7789). According to the first two sets of criteria, none of the children were underweight, whereas, according to the WHO criteria, one of the boys was underweight. The Kendall test did not demonstrate any significant difference between the three sets of criteria (coefficient of concordance for boys was W < 0.0004 and for girls it was W < 0.0008, with p = 1.00). There was a greater proportion of assessments that did not agree among the boys, at 15.13%, while for the girls this figure was 13.04%. A significant tendency was observed for the difference between the criteria to increase with age among the boys (chi-square for tendencies = 6.552, p = 0.0105), which was evident on the graph and was independent of nutritional status. CONCLUSIONS The criteria used here converged on the same result, without discrepancies between them or advantages for either. Nevertheless, among the boys there was a significant tendency for the diagnoses to differentiate and BMI to increase with age, which is a warning to take care when choosing among criteria.