[Bone fragility in type 1 diabetes and type 2 diabetes.]

Diabetes mellitus causes hyperglycemia due to resistance to insulin action in peripheral organs in addition to progressive loss of β-cell function, thus it is involved in the development and progression of diabetic microangiopathy(retinopathy, nephropathy, and neuropathy). In addition, abnormalities of bone metabolism is regarded as a chronic complication related to both type 1 diabetes and type 2 diabetes. Accumulating evidence suggests that type 1 diabetes patients had decreased bone mineral density(BMD)and the fracture risk in the femoral neck is markedly higher, when compared to non-diabetic patients. A lack of insulin level in the portal vein is associated with systemic deficiencies of Insulin-like growth factor-1(IGF-1), known as growth-promoting polypeptide essential for promoting growth and bone formation. Thus, loss of IGF-1 play a crucial role for the pathogenesis of reduced BMD in type 1 diabetes. In type 2 diabetes, despite high bone mineral density with obesity, several studies have shown that men and women with type 2 diabetes mellitus are at increased risk for bone fracture. In other words, unlike type 1 diabetes patients, an increase in the risk of fracture in type 2 diabetes is significantly related to compromised bone quality, the other factor of impaired bone strength.