Introduction

The field of body composition research is a multidisciplinary effort that serves multiple goals. It is very technology oriented, and a great deal of effort is expended on discussion of the techniques, and their validation and cross-calibration. For studies involving infants, children and adolescents, this is of particular concern, because techniques that are of proven accuracy in adults may be fraught with error in children due to changes in the size and composition of body compartments during development. Consequently, standard approaches used in adults may not be applicable or safe for use with children. This review is targeted at techniques for assessing body composition, and includes a disproportionate discussion of those techniques most feasible and practical for use with children. Considerations of the methodological assumptions and of the analysis and presentation of body composition results for children also are reviewed.

Basic concepts

Body composition assessment involves quantification of the amount and relative proportions of fat, muscle and bone, and their chemical components. Significant changes in body composition occur during growth and development, especially during infancy and puberty. Thus, body composition assessment in children is far more challenging than in adults, and serves a variety of purposes. First, it provides a better understanding of growth processes by describing changes in the size of body compartments and the chemical composition of the body. Infants and children are not miniature adults, and knowledge of their unique differences in body composition is key to understanding the biology of the human species.