Recommendations for the use of body mass index for the classification of overweight and obese children and adolescents

Abstract

Brazilian national data were used to compare body mass index (BMI) cutoff values proposed by Cole et al. (2000), which are based on statistical criteria of continuity to adult cutoff values, and those proposed by Must et al. (1991), which are recommended by the World Health Organization (WHO). According to the cutoff points proposed by each author, 5,736 children and adolescents were classified as of normal weight, overweight, or obese. These classifications were compared by 3×3 tables, and a kappa index and a confidence interval were calculated. The good concordance (kappa = 0.82) between the two cutoff values supports the hypothesis that studies on the prevalence of childhood obesity and overweight based on these two different methods can be compared. However, some differences in classification can arise when these methods are used to classify individuals. Further studies to evaluate morbidity and mortality and the classification of obesity in children and adolescents are necessary.