Field methods in the evaluation of obesity in children and adolescents: [revision]

In large samples, the methods for obtaining information on obesity need to be simple, inexpensive and reasonably accurate. This review deals with articles focusing on various field methods for the evaluation of body composition. The Bioimpedance and Near Infrared methods are simple to execute but their advantage in relation to Body Mass Index is obscure. Although the Bioimpedance and near infrared methods provide estimates of fat content, they may be no better than waist circumference measurements. The latter does not distinguish body fat but points to a more direct relationship concerning health risk. Regardless of the advantages, waist circumference continues to be under discussion: there is a lack of standardization and no reference populations or cutoff points have been established. No perfect method exists, but the number of errors could be reduced, if care were taken in drawing up protocols, standardization, and the analysis of sample properties. Em amostras grandes, os metodos para se obter informacoes sobre a obesidade precisam ser simples, baratos e razoavelmente acurados. Essa revisao narrativa foi desenvolvida a partir de artigos e focara alguns metodos de campo para avaliacao da composicao corporal. Os metodos de Bioimpedância e do Infravermelho sao de simples execucao, baratos mas sua vantagem em relacao ao Indice de Massa Corporea e obscura. Apesar dos metodos de Bioimpedância e Infra-vermelho apresentarem estimativas da porcentagem de gordura, talvez nao sejam superiores as medidas de circunferencia da cintura. Essa nao distingue a gordura corporal mas aponta para uma relacao mais direta com o risco a saude. Apesar das vantagens, a ciurcunferencia da cintura continua em discussao: faltam as padronizacoes, o estabelecimento de populacoes de referencia e pontos de corte. Nao ha metodo perfeito, mas os erros serao diminuidos se houver precaucao na elaboracao dos protocolos, na padronizacao e na analise das caracteristicas da amostra.