- Medical conditions which might alter bone metabolism, including hyperparathyroidism, hypoparathyroidism, hyperthyroidism, hypothyroidism, Paget's disease, malabsorption, or Cushing's syndrome, and hypogonadism, hypocalcemia, hypercalcemia, hypophosphatemia, hypomagnesemia, hypermagnesemia, osteopetrosis, osteomalacia, and recent (within one year) history of fracture or prolonged bedrest.