Metabolic Syndrome in Bone Marrow Transplant Survivors

Life for long-term bone marrow transplant patients is complicated by endocrine late effects including growth hormone (GH) deficiency, thyroid hormone deficiency and sex steroid deficiency. Recently, studies have also identified problems with metabolic syndrome in adult bone marrow transplant (BMT) survivors. Metabolic syndrome has been identified as a constellation of insulin resistance, truncal obesity and high lipid levels (dyslipidemia) and is associated with an increased risk of type 2 diabetes and cardiovascular disease. Thus the early identification of metabolic syndrome is important. To date, studies have not identified how young an age metabolic syndrome begins in BMT survivors. The investigators' study will consist of two aims: 1. Evaluation of children who have survived BMT for growth hormone deficiency, abnormal lipid metabolism, hypothyroidism and gonadal dysgenesis. The investigators will utilize growth hormone stimulation testing, sex steroid levels, an oral glucose tolerance test (OGTT) and fasting lipid profile to evaluate for concomitant endocrinopathy, prediabetes and impaired glucose tolerance in a cohort of BMT survivors. 2. Cross-sectional study of peripheral and hepatic insulin sensitivity in children surviving BMT using a hyperinsulinemic euglycemic clamp and the stable isotope 6,6 \[2H2\] glucose. These aims will provide pilot data to power the first definitive study of insulin resistance in childhood BMT survivors.