 To measure volumetric BMD vBMD as well as bone architecture, peripheral quantitative computer tomography pQCT XCT-2000; Stratec, Pforzheim, Germany will be used. pQCT is able to distinguish between type of bone cortical and trabecular. For the tibia, length of the non-dominant tibia is measured as the distance from the distance between the palpated lateral condyle and the lateral malleolus. Single slices are measured 4 and 66 proximally from the distal end of the tibia. The 4 site will provide a trabecular measurement whilst the 66 site will provide a cortical measurement. 