Osteoporosis
Summary
Osteoporosis is a systemic skeletal disease characterised by low bone mass and microarchitectural deterioration, leading to bone fragility and increased fracture risk. It is defined by a DEXA T-score of -2.5 or below at the hip or spine. The most common clinical manifestations are fragility fractures, particularly of the hip, vertebrae, and wrist. FRAX (Fracture Risk Assessment Tool) calculates 10-year fracture probability to guide treatment decisions. Management involves lifestyle measures (calcium, vitamin D, weight-bearing exercise, falls prevention) and pharmacotherapy (bisphosphonates first-line, denosumab, teriparatide, romosozumab for high-risk). Treatment reduces fracture risk by 50-70%.
Key Facts
- Definition: Bone mineral density T-score ≤ -2.5 at hip or spine (DEXA)
- Incidence: 1 in 2 women and 1 in 5 men over 50 will have a fragility fracture
- Demographics: Postmenopausal women most affected; increases with age
- Pathognomonic: Fragility fracture (fracture from low-energy trauma)
- Gold Standard Investigation: DEXA scan (hip and lumbar spine)
- First-line Treatment: Oral bisphosphonate (alendronate, risedronate)
- Prognosis: Fracture risk reduced 50-70% with treatment
Clinical Pearls
FRAX Pearl: Use FRAX to calculate 10-year fracture risk. NOGG thresholds guide treatment decisions in the UK.
Vertebral Fracture Pearl: Only 1/3 of vertebral fractures come to clinical attention. Height loss greater than 4cm or kyphosis should prompt investigation.
Bisphosphonate Pearl: Take bisphosphonates fasting with water, remain upright 30 minutes. Assess dental health before starting.
Denosumab Pearl: Denosumab must not be stopped abruptly - rapid bone loss and vertebral fractures can occur. Must continue or switch to bisphosphonate.
Secondary Pearl: Always exclude secondary causes (vitamin D deficiency, thyroid, myeloma, hyperparathyroidism) before diagnosing primary osteoporosis.
Why This Matters Clinically
Hip fractures have 20% one-year mortality. Vertebral fractures cause pain and disability. Osteoporosis is preventable and treatable. Identifying at-risk patients and initiating treatment prevents fractures and saves lives.
Burden of Disease
| Statistic | Value |
|---|---|
| Lifetime fragility fracture risk (women over 50) | 50% |
| Lifetime fragility fracture risk (men over 50) | 20% |
| Hip fractures per year (UK) | 70,000+ |
| Vertebral fractures per year (UK) | 120,000+ |
| Cost to NHS | £4.4 billion/year |
Demographics
- Sex: Women 4x more affected than men
- Age: Risk doubles every decade after 50
- Ethnicity: Higher in Caucasian and Asian populations
Risk Factors
| Category | Factors |
|---|---|
| Non-modifiable | Age, female sex, family history of hip fracture, ethnicity |
| Modifiable | Low BMI, smoking, excessive alcohol, low calcium/vitamin D, sedentary lifestyle |
| Medical | Glucocorticoids, RA, malabsorption, hypogonadism, hyperthyroidism, type 1 DM |
| Fall risk | Visual impairment, neurological disease, polypharmacy |
Bone Remodelling
Normal Bone Turnover:
- Osteoclasts resorb old bone (resorption)
- Osteoblasts form new bone (formation)
- Balance maintains bone mass
Osteoporosis:
- Resorption exceeds formation
- Net bone loss
- Trabecular bone (spine) affected early
- Cortical bone (hip) affected later
Mechanisms
Primary (Postmenopausal and Age-Related):
- Oestrogen deficiency → increased osteoclast activity
- Age-related decline in osteoblast function
- Reduced calcium absorption
- Secondary hyperparathyroidism
Secondary Causes:
- Glucocorticoids: osteoblast apoptosis, reduced bone formation
- Hyperthyroidism: increased bone turnover
- Hyperparathyroidism: increased resorption
- Malabsorption: calcium/vitamin D deficiency
- Hypogonadism: loss of sex hormone bone protection
Classification
| Type | Features |
|---|---|
| Primary Type I | Postmenopausal, trabecular bone loss |
| Primary Type II | Age-related (senile), cortical and trabecular |
| Secondary | Due to identifiable cause |
Often Asymptomatic
Fragility Fractures
| Site | Features |
|---|---|
| Vertebral | Back pain, height loss, kyphosis; may be asymptomatic |
| Hip | Severe trauma, high morbidity/mortality, usually surgical |
| Wrist (Colles') | Often first presentation in younger patients |
| Other | Proximal humerus, pelvis, ribs |
Signs of Vertebral Fractures
Red Flags
[!CAUTION]
- Any fragility fracture (fracture from standing height or less)
- Significant height loss
- Prolonged glucocorticoid use (greater than 3 months, 7.5mg+ prednisolone)
- Features suggestive of secondary cause (hypercalcaemia, anaemia, ESR elevation)
General Inspection
- Height measurement (compare to historical)
- Kyphosis
- Body habitus
Spine Examination
- Thoracic kyphosis
- Lumbar lordosis loss
- Spinal tenderness (acute fracture)
- Rib-pelvis distance
Fall Risk Assessment
- Gait and balance (Timed Up and Go test)
- Vision
- Postural hypotension
- Lower limb strength
- Environmental hazards
DEXA Scan (Dual-Energy X-Ray Absorptiometry)
Gold standard for diagnosis
| T-Score | Classification |
|---|---|
| Greater than -1.0 | Normal |
| -1.0 to -2.5 | Osteopenia |
| -2.5 or below | Osteoporosis |
| -2.5 or below + fragility fracture | Severe osteoporosis |
Sites measured: Lumbar spine (L1-L4), femoral neck, total hip
FRAX (Fracture Risk Assessment Tool)
- Calculates 10-year probability of major osteoporotic and hip fracture
- Inputs: age, sex, BMI, prior fracture, parent hip fracture, glucocorticoids, RA, secondary causes, alcohol, smoking
- NOGG (National Osteoporosis Guideline Group) provides treatment thresholds
Laboratory Investigations
| Test | Purpose |
|---|---|
| Calcium | Hypercalcaemia (malignancy, HPT) |
| Vitamin D (25-OH) | Deficiency very common |
| PTH | Hyperparathyroidism |
| TFTs | Hyperthyroidism |
| FBC | Anaemia (myeloma) |
| ESR/CRP | Inflammation, myeloma |
| U&E, LFTs | Renal/liver disease |
| Serum/urine protein electrophoresis | Myeloma |
| Coeliac serology | If malabsorption suspected |
| Testosterone (men) | Hypogonadism |
Spine Imaging
- Lateral thoracolumbar X-ray or vertebral fracture assessment (VFA on DEXA)
- Identify vertebral fractures (often asymptomatic)
Management Algorithm
SUSPECTED OSTEOPOROSIS
↓
┌──────────────────────────────────────────────────────────┐
│ ASSESS FRACTURE RISK │
│ - FRAX calculation │
│ - DEXA if indicated │
│ - Check for secondary causes │
└──────────────────────────────────────────────────────────┘
↓
┌──────────────────────────────────────────────────────────┐
│ TREATMENT DECISION (NOGG) │
├──────────────────────────────────────────────────────────┤
│ Below threshold → Reassure, lifestyle advice │
│ Intermediate → DEXA then re-assess │
│ Above threshold → TREAT │
│ Fragility fracture → TREAT (no DEXA needed) │
└──────────────────────────────────────────────────────────┘
↓
┌──────────────────────────────────────────────────────────┐
│ ALL PATIENTS: LIFESTYLE + SUPPLEMENTS │
│ - Calcium 1000-1200mg/day (diet + supplement if needed) │
│ - Vitamin D 800-1000 IU/day │
│ - Weight-bearing exercise │
│ - Falls prevention │
│ - Smoking cessation, moderate alcohol │
└──────────────────────────────────────────────────────────┘
↓
┌──────────────────────────────────────────────────────────┐
│ PHARMACOTHERAPY │
├──────────────────────────────────────────────────────────┤
│ FIRST-LINE: Oral bisphosphonate │
│ - Alendronate 70mg weekly │
│ - Risedronate 35mg weekly │
│ │
│ IF INTOLERANT/CONTRAINDICATED: │
│ - IV zoledronic acid (annual) │
│ - Denosumab (6-monthly SC) │
│ │
│ IF VERY HIGH RISK/MULTIPLE FRACTURES: │
│ - Teriparatide (anabolic) or │
│ - Romosozumab then bisphosphonate │
└──────────────────────────────────────────────────────────┘
Lifestyle Measures
- Calcium: 1000-1200mg/day (dietary preferred, supplement if needed)
- Vitamin D: 800-1000 IU/day (higher doses if deficient)
- Weight-bearing and resistance exercise
- Falls prevention and home safety assessment
- Smoking cessation
- Limit alcohol (less than 3 units/day)
Pharmacotherapy
| Drug | Route | Frequency | Notes |
|---|---|---|---|
| Alendronate | Oral | 70mg weekly | First-line; take fasting, upright |
| Risedronate | Oral | 35mg weekly | Alternative oral |
| Zoledronic acid | IV | 5mg annually | If oral intolerant |
| Denosumab | SC | 60mg 6-monthly | Don't stop abruptly |
| Teriparatide | SC | 20mcg daily (2 years) | Anabolic; severe/multiple fractures |
| Romosozumab | SC | 210mg monthly (1 year) | Anabolic; then antiresorptive |
Bisphosphonate Administration
- Take fasting with plain water
- Remain upright for 30 minutes
- Do not take with other medications or food
- Assess dental health before starting (osteonecrosis of jaw risk)
Treatment Duration
- Bisphosphonates: review at 3-5 years (drug holiday if low risk)
- Denosumab: continue or transition to bisphosphonate (not stop)
- Teriparatide: maximum 2 years, then follow with bisphosphonate
Glucocorticoid-Induced Osteoporosis
- Start bone protection with glucocorticoids if:
- Age greater than 70, or
- Prior fragility fracture, or
- High-dose glucocorticoids (7.5mg+ prednisolone greater than 3 months)
| Complication | Risk | Management |
|---|---|---|
| Hip fracture | High morbidity/mortality | Surgical fixation, rehab |
| Vertebral fractures | Pain, deformity, disability | Analgesia, physiotherapy |
| Bisphosphonate-related ONJ | Rare (1 in 10,000-100,000) | Dental assessment before starting |
| Atypical femoral fracture | Rare with prolonged bisphosphonate | Consider drug holiday |
Fracture Risk Reduction
| Treatment | Hip Fracture Reduction | Vertebral Fracture Reduction |
|---|---|---|
| Alendronate | 50% | 50% |
| Zoledronic acid | 40% | 70% |
| Denosumab | 40% | 70% |
| Teriparatide | 50% | 65% |
Hip Fracture Outcomes
- 1-year mortality: 20%
- Loss of independence: 50%
- Treatment dramatically improves outcomes
Key Guidelines
-
NOGG 2021 UK Clinical Guideline — Compston JE et al. Arch Osteoporos. 2021
-
NICE TA464. Bisphosphonates for Osteoporosis — 2017
-
AACE/ACE Guidelines for Postmenopausal Osteoporosis — 2020
-
ESCEO/IOF Guidelines — European guidance
Landmark Trials
FIT (Fracture Intervention Trial) – Alendronate
- 50% reduction in vertebral and hip fractures
- PMID: 8950879
HORIZON (Zoledronic Acid)
- Annual IV zoledronic acid reduces hip fracture 40%
- PMID: 17476007
FREEDOM (Denosumab)
- Denosumab reduces vertebral fracture 70%
- PMID: 19671655
What is osteoporosis?
Osteoporosis means your bones have become weaker and more fragile, making them more likely to break. It's sometimes called "brittle bone disease."
How do I know if I have it?
A DEXA scan (bone density test) measures the strength of your bones. You may also be diagnosed if you've had a fragility fracture - a break from a minor fall or bump.
What is the treatment?
- Calcium and vitamin D to support bone health
- Medication (usually a bisphosphonate tablet once weekly) to strengthen bones
- Weight-bearing exercise
- Preventing falls
How do I take bisphosphonates?
Take alendronate first thing in the morning on an empty stomach, with a full glass of plain water. Don't eat, drink, or lie down for at least 30 minutes after.
Side effects to watch for
- Heartburn or difficulty swallowing (stop and see doctor)
- Bone, joint, or muscle pain
- Jaw pain (rare)
-
Compston JE et al. UK clinical guideline for the prevention and treatment of osteoporosis. Arch Osteoporos. 2017;12(1):43. PMID: 28425085
-
Black DM et al. Fracture risk reduction with alendronate in women with osteoporosis (FIT). J Clin Endocrinol Metab. 2000;85(11):4118-4124.
-
Black DM et al. Once-yearly zoledronic acid for treatment of postmenopausal osteoporosis (HORIZON). N Engl J Med. 2007;356(18):1809-1822. PMID: 17476007
-
Cummings SR et al. Denosumab for prevention of fractures in postmenopausal women (FREEDOM). N Engl J Med. 2009;361(8):756-765. PMID: 19671655
-
Kanis JA et al. FRAX and the assessment of fracture probability in men and women from the UK. Osteoporos Int. 2008;19(4):385-397. PMID: 18292978
-
Cosman F et al. Clinician's Guide to Prevention and Treatment of Osteoporosis. Osteoporos Int. 2014;25(10):2359-2381. PMID: 25182228
-
NICE Technology Appraisal TA464. Bisphosphonates for treating osteoporosis. 2017.
Viva Points
"Osteoporosis is defined by T-score -2.5 or below on DEXA. Use FRAX to calculate 10-year fracture risk and NOGG for treatment thresholds. All patients need calcium, vitamin D, exercise. First-line treatment: oral bisphosphonate (alendronate 70mg weekly). Denosumab if intolerant. Teriparatide/romosozumab for very high risk. Always exclude secondary causes."
Key Examination Points
- Height measurement
- Kyphosis
- Tenderness over spine
- Fall risk assessment
Common Mistakes
- ❌ Not measuring height or checking for height loss
- ❌ Forgetting to exclude secondary causes
- ❌ Bisphosphonate administration errors
- ❌ Stopping denosumab abruptly
- ❌ Not treating after fragility fracture (treatment gap)
Last Reviewed: 2026-01-01 | MedVellum Editorial Team