Revalidation for paediatricians: Important lessons for all

摘要

BCA subdivides the crude BM1 phenotype into more sharply divided phenotypes. These are characterized by differences in fat mass, regional fat depots, muscle and organ masses or bone mineral content. There are up to 30-40 individual body components, which can be combined at different levels.8 About 70 years ago, BCA started with the classical Behnke's two component model; this is still the most widely applied model dividing body weight into fat mass and fat-free mass (FFM, that is, the actively metabolizing body component.8'9 Present models of body composition refer to five different levels, that is, 'atomic' (including the 11 major elements, H, O, N, C, Na, K, Cl, P, Ca, Mg, S), 'molecular' (including 6 components, lipid, water, protein, carbohydrates, bone minerals, soft tissue minerals), 'cellular' (that is, 3 or 4 components, cell mass, extracellular fluids, extracellular solids, where cell mass can be divided into fat and actively metabolizing body cell mass) and 'tissue-organ levels' (= 4 major tissues, adipose tissue, skeletal muscle, visceral organs, bone with further organ-level components such as brain, liver, kidneys, heart, spleen) resulting in many body components or so-called multicomponent models.