The blood tests are bone turnover markers (Alkaline phosphatase[ALP], Procollagen Type 1 N-Terminal Propeptide[P1NP] and C-Terminal Telopeptide of Type 1 Collagen[CTX]). The first blood test will be done by the researcher (Dr Sithambaram) in the SCHCRF and the subsequent 6 blood tests can be done by the research nurse/researcher at the participant's home. Blood samples taken will be allowed to clot for ½ an hour. Samples will be spun at 2500 rpm for 10 minutes at 4°C. The centrifuged sample will be stored in SCHCRF at -80°C. Blood tests will be analysed in the Mellanby Centre for Bone Research, University of Sheffield.