Comparison of body mass index, the bioimpedance electric and waist circumference in childhood obesity classification

Childhood is a period of rapid development and growth, characterized by major changes, particularly with regard to body composition. Considering that this is closely related to the nutritional and health status, the review takes on added importance in this period of life. There are currently many and varied methods for assessing body composition, which are based on different physical principles and models, and to characterize the overall body composition and undifferentiated form or in a specific manner differentiate the various body compartments.1 The body composition can be measured by simple methods such as anthropometry or by more sophisticated measurements such as underwater weighing, plethysmography, the bioimpedance Electric (BIA) absorptiometry X X Dual Frequency (DEXA), Magnetic Resonance (MRI), Computed Axial tomography (CAT), among others.2 Despite the DEXA method is considered a gold standard for the evaluation of body composition, it may have some limitations, including the cost, only be possible to use in small studies and complexity of the method.3 The Body Mass Index (BMI) is a less expensive, simple and reproducible method to assess obesity, but its use has many drawbacks, including the fact that not distinguish fat mass, lean mass, or bone.4 Therefore the use of BMI remains under discussion due to underestimate excess fat in children.5 Another disadvantage relates to the fact that the relationship between BMI and the body fat percentage is not the same between different ethnic groups, since a given BMI may not correspond to the same degree of fatness among different populations.6 There is evidence suggesting that Asians have lower BMI but higher percentage of body fat than Caucasians, therefore, the International Obesity Task Force (IOTF), International Association for The Study of Obesity (IASO) and the World Health Organization (WHO) They proposed a new criterion to define overweight and obesity in these regions based on their risk factors and morbidity. Currently, to set the Child obesity have been used different references. In the United States use the curves produced by the Centers for Disease Control and Prevention (CDC) in 2000, also used in Canada and Australia. England developed curves (UK90) based on extensive research data carried out between 1978-90, at about 30,000 individuals.