INTRODUCTION: There is not a consensus about the diagnostic of overweight and obesity in children. The recommendations by World Health Organization (WHO), Center of Disease Control (CDC) and International Obesity Task Force (IOTF) are more commons. There are differences among the index (BMI or score), population (american or others) and/or conception. OBJECTIVES: to compare three nutritional status classifications in a representative sample of preschoolers, whose attended regularly public day-care centers in São Paulo city. METHODS: Twenty-one day-care centers and 676 children, between 2 and 7 years old, were randomly assigned by a cluster sampling in two stages. Each child was classified about his nutritional status using three different criteria and the concordance among the indexes were analyzed by Kappa statistics. The prevalence of overweight was 18.6%, 13.2% and 12.2% according to the indexes WHO, CDC and IOTF, respectively. RESULTS: About the overweight, the range of prevalence difference was 2,7% until 12,4% and for obesity, the range was 3,7% until 5,4%. Highlighting the difference between indexes proposed by CDC and IOTF, mainly in males obesities, which the CDC was 2.6 higher. The concordance was low (k < 0,40) only between males overweight classified by CDC and IOTF. CONCLUSIONS: It is the possible to compare studies which use different criteria to classify nutritional status in children but they need to be done carefully.
obesity; preschoolers; nutritional status index; day-care centers
