Recent studies suggest that oral antidiabetic medications of the thiazolidinedione class, such as rosiglitazone (Avandia) and pioglitazone (Actos), may weaken bones, increasing the risk of fractures in older women with diabetes. The proposed study will test whether drugs of the DPP-4 inhibitor class, such as sitagliptin (Januvia), have beneficial effects on bone turnover by increasing the activity of GLP-1 and GIP. Results of this pilot study may suggest the need to perform longer-term studies to determine whether DPP-4 inhibitors increase bone mineral density and reduce the risk of fractures in patients with diabetes.