Changes in body composition in children following kidney transplantation.

Rapid weight gain has been observed following kidney transplantation. To determine the accompanying changes in body composition, we studied 8 patients (7 females, 1 male) aged 3-17.5 years who underwent renal transplantation. Body composition measurements included weight, height, triceps skinfold thickness, total body potassium, total body water, and extracellular water. Excessive weight gain was observed in most of the patients. Weight as a percentage of ideal weight for height increased from 96.0 +/- 13.8 to 116.3 +/- 13.0% (p less than 0.01). This was accompanied by a gain in fat mass in the first 3 months and a subsequent increase in lean body mass in the next 3 months. Extracellular water was increased before transplantation (32.9 +/- 6.5% of body weight) and returned to normal (27.3 +/- 8.6%) 3 months after transplantation (p less than 0.01). The weight gain following kidney transplantation in children resulted mainly from increases in adipose tissue and lean body mass, and was not related to water retention.