Glucose metabolism and body composition in young adults treated with TBI during childhood

After SCT in childhood, survivors may develop disorders of glucose metabolism. The role of obesity is controversial. We measured insulin sensitivity using the homeostasis model assessment (HOMA) and the frequently sampled i.v. glucose tolerance test (FSIVGTT), as well as body composition using dual-energy X-ray absorptiometry in 18 young adults median 18.2 years after SCT and compared them with matched controls. We also measured growth hormone (GH) secretion, and levels of leptin and adiponectin. HOMA showed insulin resistance in eight patients (44%), as opposed to none of the controls (P=0.008) and FSIVGTT showed a decreased sensitivity index in the patients (2.98 vs 4.54 mU/L/min, P=0.042). Dual energy X-ray absorptiometry showed a higher percentage fat mass in the patients (34.9 vs 24.3%, P=0.011), which correlated inversely with the sensitivity index (r=-0.52, P=0.032). The patients had a lower peak value of GH (GH(max) 9 vs 20.7 mU/L, P=0.002). Time post SCT correlated with percentage fat mass and inversely with GH(max). The patients had higher levels of leptin and lower levels of adiponectin, even after adjustment for fat mass. We propose that the decreased insulin sensitivity may primarily be explained by the adverse body composition, which may owe to long-standing GH deficiency.