Body composition in adult growth hormone-deficient men, assessed by anthropometry and bioimpedance analysis

Anthropometry and bioimpedance analysis (BIA) were used to assess body composition in 42 GH-deficient (GHD) adult males (mean age, 27.2 +/- 4.7 yr). During childhood, all patients had received GH treatment for a mean period of 8.4 +/- 3.8 yr. At the start of this study, GH therapy had been discontinued for a mean period of 7.5 +/- 4.5 yr. Eighteen patients had isolated GH deficiency (I-GHD). Twenty-four patients had multiple pituitary hormone deficiencies (M-PHD), substituted adequately. Compared to age- and sex-matched controls, the sum of skinfolds measured at 7 different sites was significantly higher in I-GHD and M-PHD patients [controls, 73.1 +/- 25.4 mm; I-GHD patients, 102.1 +/- 37.7 mm (P less than 0.001); M-PHD patients, 126.8 +/- 35.4 mm (P less than 0.001)]. The increase in sc fat deposition was most pronounced on the trunk, particularly in the breast and abdominal area. Total body muscle mass was significantly lower in GHD patients (P less than 0.001). In patients, body muscle mass and plasma somatomedin-C level were positively correlated (r = 0.43; P less than 0.005). Total body resistance measured by whole body BIA was significantly higher in the patient group and was negatively correlated with plasma somatomedin-C (r = -0.53; P less than 0.001). The high resistance values observed in GHD patients could only in part be explained by their lower lean body mass. The most important cause, however, was an increase in specific electrical resistance of the lean body mass (LBM), reflecting relative dehydration. We conclude that GH deficiency in adult males is associated with an increase in sc fat and a decrease in body muscle mass. In addition, there is a qualitative change in LBM. The BIA data indicate that in these patients, the hydration state of the LBM is lower than normal, due to a decrease in extracellular water.