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: To compare bone structure and density between type 1 and type 2 diabetes patients and to investigate fracture associations.

DESIGN: 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.

MAIN OUTCOME MEASURES: Bone density and structure was assessed by dual energy x-ray absorptiometry and high resolution peripheral quantitative CT. 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 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 to 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.