Osteoporosis — Causes, Symptoms & Treatment Guide — Symptoms, Causes & Treatment | MyMedicPlus

Osteoporosis is a systemic skeletal disease characterised by reduced bone mineral density (BMD) and deterioration of bone microarchitecture, resulting in increased bone fragility and risk of fracture. It affects approximately 200 million people worldwide and is a leading cause of morbidity, disability, and healthcare costs, particularly in postmenopausal women and older adults. One in three women and one in five men over 50 will sustain a fragility fracture — a fracture caused by minimal trauma (falling from standing height or less). Hip fractures are the most serious consequence, carrying 20–30% one-year mortality and 40% failure to regain pre-fracture mobility. Diagnosis is made by DEXA scan: T-score ≤−2.5 indicates osteoporosis; T-score −1 to −2.5 indicates osteopenia (at-risk state). Osteoporosis is defined by a T-score at or below -2.5 on DEXA bone density scan; osteopenia is T-score between -1.0 and -2.5 — a stage where fracture risk prevention through lifestyle and supplementation is important.

Peak bone mass is achieved by age 30; bone density then gradually declines. In women, accelerated bone loss occurs in the 5–10 years following menopause due to oestrogen deficiency (oestrogen inhibits osteoclast-mediated bone resorption). Primary osteoporosis affects postmenopausal women and older men. Secondary osteoporosis has identifiable causes: glucocorticoid use (most common secondary cause — prednisone ≥5 mg/day for ≥3 months requires prophylaxis), hypogonadism, hyperparathyroidism, hyperthyroidism, coeliac disease (malabsorption), inflammatory bowel disease, multiple myeloma, chronic kidney disease, and excess alcohol. Risk factors include: female sex, age >65, premature menopause (<45), family history of hip fracture, low body weight (BMI <18.5), smoking, excessive alcohol, physical inactivity, low calcium/vitamin D intake, and prior fragility fracture (the strongest predictor).

Osteoporosis is typically asymptomatic ('silent disease') until a fracture occurs. Fragility fractures — the clinical manifestation of osteoporosis — occur at characteristic sites: vertebral compression fractures (most common, often painless or causing acute back pain, progressive height loss, kyphosis — 'dowager's hump'), hip fractures (femoral neck or intertrochanteric — cause sudden hip pain with inability to weight-bear, external leg rotation), wrist fractures (Colles' fracture — fall on outstretched hand), and proximal humerus fractures. Vertebral fractures may cause chronic back pain, restriction of movement, and respiratory compromise from rib cage compression in severe kyphosis. Height loss of >4 cm from peak height suggests vertebral fractures.

DEXA (dual-energy X-ray absorptiometry) measures bone mineral density at the lumbar spine and hip, generating a T-score (standard deviations from young adult peak BMD) and Z-score (age-matched). T-score ≤−2.5 = osteoporosis; −1 to −2.5 = osteopenia. FRAX (Fracture Risk Assessment Tool) calculates 10-year probability of major osteoporotic fracture and hip fracture using clinical risk factors ± BMD, guiding treatment decisions. Blood tests exclude secondary causes: calcium, phosphate, alkaline phosphatase, albumin, eGFR, thyroid function, PTH, 25-OH vitamin D, testosterone (men), full blood count, protein electrophoresis (multiple myeloma). Vertebral fracture assessment (VFA) or lateral spine X-ray identifies incident vertebral fractures. Bone turnover markers (P1NP, CTX) monitor treatment response.

All patients: calcium 1,000–1,200 mg/day (dietary or supplement) and vitamin D 800–1,000 IU/day — essential cofactors for all osteoporosis treatments. Bisphosphonates are first-line antiresorptive therapy: alendronate 70 mg weekly or risedronate 35 mg weekly (oral — must be taken on empty stomach with large water, remain upright 30 minutes) reduce vertebral fracture risk by 40–50% and hip fracture risk by 25–40%. Zoledronate 5 mg IV annually is highly effective and preferred when GI intolerance or poor oral adherence exists. Denosumab (anti-RANKL monoclonal antibody) 60 mg SC every 6 months reduces fracture risk by 70% at spine — must not be stopped abruptly (rebound vertebral fractures). Romosozumab (anti-sclerostin, 210 mg SC monthly for 12 months) is an anabolic agent for very high-risk patients (prior hip or multiple vertebral fractures) — increases bone formation while reducing resorption. Teriparatide (PTH analogue — 24 months) is anabolic for severe osteoporosis. Hip protectors reduce fracture risk in falls-prone patients.

Fragility fractures are the defining complication of osteoporosis. Hip fracture carries 20-30% one-year mortality — most fracture-related deaths in older adults; 40% of survivors fail to regain pre-fracture functional independence and 50% require long-term care. Each standard deviation reduction in BMD approximately doubles hip fracture risk. Vertebral compression fractures cause acute severe back pain, progressive height loss (3-20 cm over multiple fractures), thoracic kyphosis ('dowager's hump') leading to restrictive lung disease from rib cage compression, and gastro-oesophageal reflux from diaphragm compression; multiple vertebral fractures increase mortality 2-3 fold. Wrist fractures (Colles') cause persistent pain, carpal tunnel syndrome, and reduced grip strength. Cascade fracture effect: a single vertebral fracture increases the risk of subsequent vertebral fracture 5-fold within the next 12 months. Prolonged bed rest and immobility following fractures cause deep vein thrombosis, pulmonary embolism, and pneumonia. Chronic pain, deformity, restricted mobility, and loss of independence lead to depression, social isolation, and dependence on carers.

Build peak bone mass during childhood and adolescence through adequate calcium, vitamin D, and weight-bearing exercise. In adulthood, weight-bearing exercise (walking, dancing, jogging), resistance training, and balance exercises (Tai Chi) reduce falls risk and maintain BMD. Ensure calcium intake of 1,000–1,200 mg/day from dietary sources (dairy, fortified foods, almonds, sardines). Maintain vitamin D sufficiency (25-OH vitamin D ≥50 nmol/L) — supplement 800–1,000 IU/day if deficient. Quit smoking (smokers have 25% lower BMD). Limit alcohol to fewer than 14 units/week. Fall prevention at home: remove loose rugs, install grab rails, ensure adequate lighting, review medications causing dizziness (antihypertensives, sedatives). Glucocorticoid users should receive bisphosphonate prophylaxis from the outset.

Go to the emergency department immediately after any fall causing hip, wrist, or back pain — even if pain seems mild, fragility fractures can be present without deformity, and delayed diagnosis of a hip fracture is dangerous. Acute severe back pain after minimal trauma or lifting may indicate a vertebral compression fracture requiring urgent assessment. See your doctor if: you have lost more than 2–3 cm in height (possible vertebral fractures); you are a postmenopausal woman over 50 or a man over 70 — DEXA screening should be discussed; you take long-term glucocorticoids, as bone protection should be started promptly; or you have had any fracture after minimal trauma at any age.