Osteoporosis: Screening and Diagnosis

Osteoporosis: Screening and Diagnosis

In Plain Language

Who Should Be Screened for Osteoporosis?

For Women:

Age 65 and older: All women should be screened at least once – even without symptoms.
Under 65: Screening only if risk factors are present, such as:
- Family history of osteoporosis
- Early menopause
- Smoking
- Low body weight
- Bone fractures
- Long-term use of cortisone (glucocorticoids)

For Men:

Age 70 and older: Screening is recommended.
Ages 50–69: Screening only if there are risk factors, such as:
- Bone fractures
- Cortisone therapy
- Low testosterone
- Heavy alcohol or tobacco use
- Chronic diseases (e.g., COPD, rheumatoid arthritis)

FRAX® – Fracture Risk Assessment Tool

FRAX® is an online tool that calculates your 10-year risk of a bone fracture.
It uses information like age, gender, weight, previous fractures, and lifestyle.
A bone density scan (DXA) is not always necessary but can improve accuracy.

Link: https://frax.shef.ac.uk/FRAX/

Bone Density Scan (DXA)

The DXA scan measures how strong your bones are.
It takes 10–15 minutes, is painless, and uses very low radiation.

Where is it measured?

Lower back (lumbar spine)
Hip (femoral neck)
(Optional: forearm or whole body)

Result: T-Score

T-score ≥ –1.0 → normal
T-score between –1.0 and –2.5 → osteopenia (low bone mass)
T-score ≤ –2.5 → osteoporosis

Lab Tests

Some conditions can cause osteoporosis. That’s why a blood test is done, checking:

Calcium, phosphate, vitamin D, kidney function
Thyroid, liver, protein levels
Inflammation markers
Hormone levels (e.g., testosterone)

Additional Examinations

Spinal X-rays (if needed)
Medical history questions, such as:
- Bone fractures
- Hormone changes
- Cortisone use
- Nutrition, physical activity, fall risk

Summary

Many people over 50 have osteoporosis or are at risk.
Early diagnosis helps prevent fractures.
Tools like FRAX®, DXA scans, and lab tests are useful to assess your risk.

Osteoporosis Diagnostics – Recommendations and Risk Assessment

Diagnostic Recommendations Vary by Country

In most countries, osteoporosis screening is recommended based on age and risk factors:

For Women:

≥ 65 years: All women should be screened at least once, even without risk factors.
< 65 years: Screening is recommended if risk factors are present, such as:
- Family history of osteoporosis
- Early menopause
- Smoking
- Low body weight
- Fractures
- Long-term cortisone use

For Men:

≥ 70 years: Routine screening is recommended, though less frequently performed than in women.
Ages 50–69: Screening only with risk factors, such as:
- Fractures after age 50
- Long-term glucocorticoid therapy
- Hypogonadism (testosterone deficiency)
- Alcohol or tobacco abuse
- Chronic diseases (e.g. COPD, rheumatoid arthritis, liver or kidney disease)

FRAX® – Internationally Recognized Risk Assessment Tool

FRAX® (Fracture Risk Assessment Tool) estimates the 10-year probability of a hip fracture and other major osteoporotic fractures.
It does not require a bone density measurement (DXA), which is often unreliable in younger patients.
It is based on an individual risk profile.

FRAX® Input Factors and Meaning:

Input Factor	Meaning
Age	Higher age = higher risk
Sex	Women generally at higher risk
Weight & Height	Used to calculate BMI
Previous fractures	Especially after low-impact trauma
Parental hip fracture	Indicates family history
Smoking	Increases fracture risk
Alcohol (>3 units/day)	Increases fracture risk
Glucocorticoid use	Long-term therapy (e.g., Prednisolone)
Rheumatoid arthritis	Autoimmune inflammatory condition
Other secondary causes	e.g., diabetes, liver disease, hypogonadism
(Optional) T-Score (DXA)	Improves risk estimate if bone density is known

Developed by the University of Sheffield (UK) with support from the WHO
https://frax.shef.ac.uk/FRAX/

Prevention

The risk of osteoporosis can be significantly reduced through:

Exercises to improve balance, coordination, and muscle strength
Fall prevention
Bone-friendly diet and lifestyle
Avoiding (if possible) medications or habits that increase fracture risk

Basic Diagnostic Workup Includes:

Detailed medical history (anamnesis) and physical exam
Bone density measurement (DXA)
Laboratory tests
X-rays of lumbar and thoracic spine (in two planes)

Medical History (Important Clues):

Back pain
Low intake of dairy products
Frequent consumption of cola drinks
Smoking (>20 cigarettes over 10 years)
Corticosteroid use longer than 6 months
Inflammatory bowel disease
Prone to falls
Overactive thyroid (hyperthyroidism)
Late menarche (after age 15)
Last period before age 46
Uterus/ovary removal before age 46
Hormone replacement therapy (HRT) during menopause
Fractures after minor trauma
Fractures in first-degree relatives

Bone Densitometry (DXA)

Image used under license from Shutterstock.com.

A DXA scanner (also called DEXA) is a medical imaging device used to measure bone density.
DXA stands for:
Dual-Energy X-ray Absorptiometry

Purpose of the DXA Scan

The DXA scan is used for:

Diagnosing osteoporosis
Estimating the risk of bone fractures
Monitoring treatment effectiveness in bone loss

How Does a DXA Scanner Work?

The device uses two X-ray beams with different energy levels to distinguish bone from soft tissue.

Step-by-step:

Two X-ray sources emit low-dose radiation with different energy through the body.
A detector measures how much radiation passes through.
Because bones absorb more radiation than soft tissues, bone density (BMD) can be calculated.
Results are reported in g/cm² and interpreted using T-scores and Z-scores.

Where Is the Measurement Taken?

Standard measurement sites include:

Lumbar spine (lower back) → sensitive for early detection
Femoral neck (hip) → important for fracture risk
(Optional) Forearm or whole body → used if hip prosthesis is present

Interpreting Results

T-Score: Comparison to a healthy young adult

≥ –1.0 → Normal
Between –1.0 and –2.5 → Osteopenia (early bone loss)
≤ –2.5 → Osteoporosis
(based on WHO classification)

Z-Score: Comparison to people of the same age and sex
Useful in:

Children
Men under 50
Premenopausal women

Advantages of DXA

Very low radiation dose (~1–6 μSv, less than a chest X-ray)
Fast (approx. 10–15 minutes)
Non-invasive
Repeatable for monitoring therapy

Comparison of Common Bone Density Measurement Methods

Method	Principle	Sites Measured	Radiation	Advantages	Disadvantages	Typical Use
DXA (DEXA)	Dual-energy X-ray absorptiometry	Spine, hip, forearm	Very low (1–6 μSv)	Gold standard, standardized, fast	No info on bone microstructure	Diagnosis, therapy monitoring
QCT	CT with 3D bone analysis	Spine, hip	High (50–300 μSv)	Measures trabecular bone separately	High radiation, expensive, limited availability	Research, special cases
pQCT	High-res CT for extremities	Radius, tibia	Medium (5–15 μSv)	Structural & strength assessment	Not a standard method, only peripheral sites	Research, pediatrics, sports
QUS	Ultrasound via heel bone	Heel (calcaneus)	None	Portable, no radiation, inexpensive	No direct BMD value, variable results, not WHO-certified	Screening, low-resource settings
RA	Bone measurement via hand X-ray	Metacarpal bones	Low	No extra devices needed	Outdated, imprecise, not standardized	Historical use only

Key Differences at a Glance:

DXA is the gold standard for clinical diagnosis and monitoring of osteoporosis.
QCT/pQCT also provides information on bone structure and strength, but involves higher radiation exposure.
Ultrasound (QUS) is radiation-free, but less accurate – suitable for screening, not for diagnosis.
Radiogrammetry is no longer clinically relevant today.

Laboratory Diagnostics

Recommended Lab Tests to Exclude Secondary Osteoporosis or Osteomalacia:

Inflammatory markers: ESR (BSG), CRP
Complete blood count (CBC)
Serum tests:
- Calcium
- Phosphate
- Creatinine
- Alkaline phosphatase (AP)
- GGT (gamma-glutamyl transferase)
- Basal TSH (thyroid function)
- Total protein, protein electrophoresis

In primary osteoporosis, these lab values are usually normal.

Findings in Secondary Forms of Osteoporosis:

Condition	Typical Lab/Clinical Findings
Osteomalacia	↑ Alkaline phosphatase, ↓ Calcium, ↓ Phosphate
Multiple myeloma	↑ ESR, monoclonal gammopathy (protein electrophoresis)
Renal osteopathy	↑ Creatinine, ↑ Urea
Idiopathic hypercalciuria	Kidney stones
Hypogonadism	History, clinical signs, ↓ Testosterone
Anorexia nervosa	Low weight, history
Primary hyperparathyroidism	↑ Calcium
Hyperthyroidism	History, clinical signs, ↓ TSH
Glucocorticoid-induced osteoporosis	History, clinical use of steroids
Diabetes mellitus	Abnormal blood glucose (BG)
Malabsorption	Vitamin D deficiency