Body Water, Lean Body and Fat Mass of Healthy Children as Measured by Deuterium Oxide Dilution

Body composition of 165 healthy children was measured using the well-established method of deuterium oxide (2H2O) dilution. After distribution of an oral load of 2.0 ml 2H2O/kg body weight body water was estimated from the 2H2O concentration in urine. Lean body mass was then calculated from body water using previously published age dependent ratios of the water content of the lean body mass. Fat mass was calculated as the difference of body weight and lean body mass. A good correlation was found between body water and body weight. Linear regression revealed TBW = 0.589 BW + 0.728 (r = 0.99). Body water, lean body mass and fat mass were found to change with age. The fat content of the body increases during the first six months of life. It then decreases until four to five years then rising again until 15 years of age.