Bone Structure and Predictors of Fracture in Type 1 and Type 2 Diabetes

Context: Type 1 and type 2 diabetes mellitus are associated with an increased risk of fracture. Objective: The objective of the study was to compare the bone structure and density between type 1 and type 2 diabetes patients and to investigate fracture associations. Design: This was a cross-sectional study. Setting and Patients: Physician-diagnosed type 1 and type 2 diabetes patients were included from the outpatient clinics at two university hospitals participated in the study. Main Outcome Measures: Bone density and structure were assessed by dual-energy x-ray absorptiometry and high-resolution peripheral quantitative computed tomography. Blood samples were collected for bone turnover markers. Prevalent vertebral fractures were assessed by vertebral fracture assessment and x-ray, and incident fractures were collected from The Danish National Hospital Discharge Register. Results: Bone mineral density (BMD) was higher in type 2 than type 1 diabetes patients at the hip, femur, and spine; however, only the hip differed in multivariate-adjusted models. Bone tissue stiffness at the tibia was increased in type 2 diabetes patients also in adjusted models. Sclerostin levels were inversely associated with fracture in type 1 diabetes patients. The patients with the highest tertile of sclerostin had an 81% decreased risk of a fracture compared with the lowest tertile. Conclusions: Type 1 and type 2 diabetes patients differ in BMD of the hip and tissue stiffness at the tibia. Sclerostin may be a marker independent of BMD to predict fractures in type 1 diabetes patients and thus potentially of clinical importance. Studies with longer follow-up are needed.