Assessment of regional body composition by dual energy X-ray absorptiometry in hypopituitary adults before and during growth hormone treatment

We have assessed total-body and regional fat content in hypopituitary adults before and during growth hormone (GH) therapy using dual energy X-ray absorptiometry (DEXA). At baseline, 41 patients (20 men and 21 women) were compared with 82 matched controls (44 men and 38 women). Twenty-six patients subsequently participated in a double-blind placebo-controlled GH treatment trial for 6 months (12 on GH and 14 on placebo) followed by a 12 months open trial. GH daily dose was 0.04±0.01 IU/kg. Soft tissue composition was measured in the total-body and the main regions (arms, trunk and legs). At baseline, total-body percentage fat was significantly higher in patients than in controls (men: 24.4±6.4 vs 18.9±6.3%, P<0.01; women: 37.2±7.6 vs 30.1±8.8%, P<0.01). Percentage fat was also significantly higher in patients than in controls in the trunk and the upper limbs (P<0.01, P<0.05) but not in the lower limbs. In the placebo-controlled GH treatment trial, lean tissue mass increased significantly in patients on GH treatment in the trunk (P<0.05) and in the lower limbs (P<0.01) and fat mass decreased in the upper limbs (P<0.05) but no changes were observed on placebo. During the long-term follow-up, lean tissue mass was significantly higher in the total-body and in the legs and trunk regions at 6 months (P<0.0005), 12 months (P<0.0005, P<0.01, P<0.0005) and 18 months (P<0.01, P<0.01, P<0.05) compared with pre-treatment values. Fat mass was lower at 6 months in the total-body (P<0.0005) and was lower at 6 months (P<0.01) and 12 months (P<0.05) in the trunk in comparison with pre-treatment values. Percentage fat was lower in the total-body at 6, 12 and 18 months (P<0.0005, P<0.01, P<0.05), in all the three regions at 6 months (P<0.01) and in the trunk at 6 and 12 months (P<0.005, P<0.001). In conclusion, we have objectively demonstrated a tendency for upper body fat deposition in adults with hypopituitarism and that GH treatment has beneficial effects on body fat distribution.