Postmenopausal osteoporosis explained

Postmenopausal osteoporosis is a condition in which bones become weaker and more likely to fracture, particularly after menopause. The hip, spine, and wrist are the most common sites of osteoporotic fractures. Hip fractures in particular can be life-changing, with high rates of long-term disability and elevated mortality.

Why bones change after menopause. Bone is constantly being remodelled throughout life: old bone is broken down by cells called osteoclasts and new bone is built by cells called osteoblasts. Estrogen helps keep these two processes in balance. After menopause, estrogen levels fall sharply, breakdown outpaces formation, and bone density declines, sometimes rapidly in the first several years post-menopause.

How it is diagnosed. A DXA (dual-energy X-ray absorptiometry) scan measures bone density and produces a T-score that compares the patient's bones to a young-adult reference. T-scores of -2.5 or below define osteoporosis. T-scores between -1.0 and -2.5 define osteopenia. Fracture risk assessment tools (FRAX and others) combine DXA with clinical factors to estimate fracture risk.

The two main therapy categories.

Anti-resorptive therapy: medicines that slow bone breakdown. Oral bisphosphonates (alendronate, risedronate, ibandronate) are weekly or monthly tablets. Intravenous zoledronic acid is given once a year. Denosumab is an injection given every six months. These medicines reduce fracture risk meaningfully but do not build new bone.

Anabolic therapy: medicines that stimulate new bone formation. Teriparatide and abaloparatide are daily injections used for up to two years. Romosozumab is a monthly injection used for one year and has both anabolic and anti-resorptive effects.

Sequencing pattern. For patients with severe osteoporosis or recent fracture, modern practice favours anabolic therapy first to build bone, then anti-resorptive therapy to lock in the gains. This sequence produces better outcomes than starting with anti-resorptive medicines in this population.

What to expect. Modern osteoporosis therapy substantially reduces fracture risk. Working with a doctor on the right combination, getting adequate calcium and vitamin D, doing weight-bearing exercise, and avoiding falls all contribute to long-term bone health. After a fragility fracture (a fracture from a low-impact event), evaluation for osteoporosis and initiation of appropriate therapy is particularly important; this is what fracture liaison services are designed to do.