Osteoporosis After Menopause and After Drug Therapy: The Molecular Mechanism of Bone Loss and Its Treatment

Osteoporosis is a prevalent skeletal disorder characterized by reduced bone mass and microarchitectural deterioration, leading to increased fracture risk, particularly in aging populations. Postmenopausal osteoporosis (PMOP) remains the most common primary form and results from abrupt estrogen deficiency after menopause, which disrupts bone remodeling by accelerating the receptor activator of nuclear factor-κB ligand (RANKL)-mediated osteoclastogenesis, suppressing Wnt/β-catenin signaling, and promoting inflammatory cytokine production. In contrast, drug-induced osteoporosis (DIOP) encompasses a heterogeneous group of secondary bone disorders arising from pharmacologic exposures. Glucocorticoids suppress…