 A detailed past medical history and medication history focusing on use of bone-related therapies will be taken. Subjects will be requested to record medications that could affect vitamin D metabolism, e.g. glucocorticoids, Recombinant human parathyroid hormone i.e. Teriparatide, Hormone Replacement Therapy, Rifampicin and anticonvulsants. All calcium, vitamin D and multivitamin supplements taken within 3 months prior to the clinic visit will also be recorded. 