Emerging Aspects of the Body Composition, Bone Marrow Adipose Tissue and Skeletal Phenotypes in Type 1 Diabetes Mellitus

Anthropomorphic measures among type 1 diabetic patients are changing as the obesity epidemic continues. Excess fat mass may impact bone density and ultimately fracture risk. We studied the interaction between bone and adipose tissue in type 1 diabetes subjects submitted to two different clinical managements: (I) conventional insulin therapy or (II) autologous nonmyeloablative hematopoietic stem-cell transplantation (AHST). The study comprised 3 groups matched by age, gender, height and weight: control (C = 24), type 1 diabetes (T1D = 23) and type 1 diabetes treated with AHST (T1D-AHST = 9). Bone mineral density (BMD) and trabecular bone score (TBS) were assessed by dual X-ray absorptiometry (DXA). H-1 Magnetic resonance spectroscopy was used to assess bone marrow adipose tissue (BMAT) in the L3 vertebra, and abdominal magnetic resonance imaging was used to assess intrahepatic lipids (IHL), visceral (VAT) and subcutaneous adipose tissue (SAT). Individuals conventionally treated for T1D were more likely to be overweight (C = 23.8 +/- 3.7; T1D = 25.3 +/- 3.4; T1D-AHST = 22.5 +/- 2.2 Kg/m(2); p > 0.05), but there was no excessive lipid accumulation in VAT or liver. Areal BMD of the three groups were similar at all sites; lumbar spine TBS (L3) was lower in type 1 diabetes (p < 0.05). Neither SAT nor VAT had any association with bone parameters. Bone marrow adipose tissue (BMAT) lipid profiles were similar among groups. BMAT saturated lipids were associated with cholesterol, whereas unsaturated lipids had an association with IGF1. Overweight and normal weight subjects with type 1 diabetes have normal areal bone density, but lower trabecular bone scores. Adipose distribution is normal and BMAT volume is similar to controls, irrespective of clinical treatment.