Bone is a dynamic organ in which bone formation mediated by osteoblasts balances against bone resorption mediated by osteoclasts to maintain bone homeostasis. With age, this balance gradually tilts toward bone resorption, leading to bone loss and osteoporosis. At the present study, the bone specimens from children (group A), middle-aged patients (group B), and older individuals (group C) were subjected to proteomics analysis by LC-MS/MS.