London Osteoporosis Clinic · Course 3

Bone Density Testing – Understanding DXA and Assessment

Welcome to this section on bone density testing.

Understanding your bone density is one of the most important steps in protecting your long-term bone health. A bone density scan does much more than produce a number—it helps identify your current bone strength, estimate future fracture risk, and guide the most appropriate steps to maintain or improve your bones.

Why this matters

Osteoporosis is often called the silent disease because bones can gradually weaken without causing symptoms. For many people, the first sign is a broken bone that could have been prevented.

Early assessment provides an opportunity to understand your current position before problems develop.

What you will learn

In this section you will discover:

• Who should consider bone density testing.
• What a DXA scan measures—and what it does not.
• How your results are interpreted.
• Why bone density is only one part of understanding fracture risk.
• How lifestyle, nutrition, exercise and, when appropriate, medical treatment can improve bone health over time.

Remember

You can find further information and educational resources at londonosteoporosisclinic.com.

Key Takeaway

We hope this section gives you greater understanding, confidence and practical steps you can take to protect your bone health.

Why this matters

Your bones are living tissue. They are constantly being built, repaired and remodelled throughout your life.

Understanding how bone strength changes over time helps explain why the choices you make today can influence your fracture risk many years into the future.

The Bigger Picture

During childhood and adolescence, bones grow rapidly.

• Bone strength continues to increase into early adulthood.
• Most people reach their peak bone mass between approximately 25 and 35 years of age.
• After this point, bone breakdown gradually begins to exceed bone formation.
• Following the menopause, women often experience a more rapid loss of bone because of the fall in oestrogen levels. Men also lose bone with age, but usually at a slower rate.

Understanding

Peak bone mass is like building up savings in a bank account.

The more bone you build during your younger years, the greater your reserve as you grow older. Although ageing affects everyone, entering later life with stronger bones reduces the likelihood of developing osteoporosis and suffering fractures.

Many factors influence bone strength throughout life, including:

• Genetics
• Nutrition, particularly adequate calcium and protein
• Vitamin D
• Regular weight-bearing and resistance exercise
• Hormonal health
• Smoking and excessive alcohol
• Certain medical conditions and medications

What you can do

Whatever your age, it is never too early—or too late—to improve your bone health. Small, consistent actions can make a meaningful difference:

• Stay physically active.
• Include strength and impact exercise where appropriate.
• Eat a balanced diet with adequate protein and calcium.
• Maintain healthy vitamin D levels.
• Avoid smoking and excessive alcohol.
• If you have risk factors, discuss bone health assessment with your healthcare professional.

Key Takeaway

You cannot change your age, but you can influence the strength of your bones at every stage of life. Understanding where you are today is the first step towards protecting your future independence.

Next Step

Now let's look at how bone health can be assessed and how clinicians measure bone strength and fracture risk.

Why this matters

Osteoporosis is often called the silent disease because bone loss usually causes no symptoms until a fracture occurs.

Assessing your bone health before this happens provides an opportunity to identify risk early and take steps to strengthen your bones.

The Bigger Picture

A bone density assessment is one part of understanding your overall fracture risk. Your clinician will usually consider:

• Your bone density (measured by a DXA scan)
• Your age and sex
• Previous fractures
• Family history
• Medical conditions and medications
• Lifestyle factors such as smoking, alcohol intake and physical activity

Together, these provide a much clearer picture than bone density alone.

What can a bone density test tell you?

A bone density (DXA) scan can help your healthcare professional:

• Identify whether your bone density is normal, reduced (osteopenia) or in the osteoporosis range.
• Estimate your future risk of fracture when combined with other clinical risk factors.
• Decide whether treatment is appropriate.
• Monitor changes in bone density over time.
• Assess how well lifestyle changes or osteoporosis treatments are working.

What a bone density test cannot tell you

A DXA scan is an important tool, but it is not the whole story.

Someone with a relatively normal bone density may still have an increased fracture risk because of falls, medication, underlying medical conditions or poor bone quality. Likewise, many people with osteoporosis never suffer a fracture.

This is why your scan should always be interpreted alongside your medical history and individual risk factors.

Key Takeaway

A bone density test is not simply about making a diagnosis. It provides valuable information that helps guide decisions to reduce your future fracture risk and protect your independence.

Next Step

In the next lesson, we'll explore who should consider having a bone density test and when assessment is most appropriate.

Further Reading

Private DEXA Scan London: Same-Day Results & Expert Review
Information about bone density scans, what to expect and how the results are used to guide your care.

Why Osteoporosis Treatment Is a Strategy, Not a Prescription
Your bone density is one piece of the picture — see how assessment results fit into a personalised, comprehensive approach to bone health.

Why this matters

A bone density (DXA) scan is not recommended for everyone. However, if you have certain risk factors, having a scan can identify weakened bones before a fracture occurs.

Early assessment allows you and your healthcare professional to make informed decisions about protecting your bone health.

Who should consider a bone density test?

You should discuss a bone density assessment with your healthcare professional if you are:

• A woman aged 65 years or older.
• A man aged 70 years or older.
• A woman after the menopause with one or more risk factors for osteoporosis.
• A man aged 50–69 years with significant risk factors.
• An adult over the age of 50 who has sustained a fracture after a minor fall or injury.

You may also benefit from a bone density assessment if you:

• Have lost height (particularly more than 4 cm over time).
• Develop persistent back pain that may suggest a spinal fracture.
• Have an X-ray showing thinning of the bones or a vertebral fracture.
• Have a parent who fractured their hip.
• Take long-term steroid medication.
• Have rheumatoid arthritis or certain long-term medical conditions that affect bone health.
• Have low body weight, smoke, or drink excessive amounts of alcohol.

Key Takeaway

Having one or more risk factors does not necessarily mean you have osteoporosis. It does mean that assessing your bone health may be appropriate and could help prevent future fractures.

Next Step

In the following lessons, we'll explore the different tests used to assess bone health and what each one can tell us.

Further Reading

Private DEXA Scan London: Same-Day Results & Expert Review
Information about bone density scans, what to expect and how the results are used to guide your care.

Why this matters

Not every bone health test provides the same information.

Screening tests can help identify people who may have low bone density and would benefit from further assessment. They are useful as a first step, but they cannot diagnose osteoporosis.

The Bigger Picture

Screening tests are often used in community settings, pharmacies, health fairs or some medical clinics because they are quick, convenient and relatively inexpensive.

Unlike a standard DXA scan, these tests usually measure bone density at the:

• Heel
• Wrist
• Finger
• Forearm

Common screening tests

You may come across several different technologies, including:

• QUS (Quantitative Ultrasound) – most commonly performed on the heel.
• pDXA (Peripheral Dual-energy X-ray Absorptiometry) – measures bone density in the wrist or forearm.
• pQCT (Peripheral Quantitative Computed Tomography) – provides additional information about bone structure at peripheral sites.

What screening tests can do

• Identify people who may have reduced bone density.
• Help decide whether further investigation is appropriate.
• Increase awareness of bone health and fracture risk.

What screening tests cannot do

• Diagnose osteoporosis.
• Replace a standard DXA scan.
• Monitor the effectiveness of osteoporosis treatment over time.
• Be directly compared with results from a central DXA scan.

If a screening test suggests low bone density, your healthcare professional will usually recommend a central DXA scan of the hip and/or spine for a more accurate assessment.

Key Takeaway

Screening tests are an excellent first step for identifying people who may be at increased risk. However, a central DXA scan remains the gold standard for diagnosing osteoporosis and monitoring treatment.

Next Step

Let's now look at the DXA scan, the most widely used and accurate test for assessing bone density.

Further Reading

Bone Health Tests: What Each One Actually Measures

Why this matters

Bone health assessment continues to evolve. While the DXA scan remains the reference standard for diagnosing osteoporosis, newer technologies are expanding the options available.

One of the most promising developments is Radiofrequency Echographic Multi Spectrometry (REMS).

The Bigger Picture

Unlike a DXA scan, REMS uses ultrasound technology rather than X-rays to assess bone density.

It analyses ultrasound signals from the lumbar spine and hip to estimate bone strength and fracture risk without exposing you to ionising radiation.

REMS is increasingly being used in specialist centres and is supported by a growing body of clinical research.

Potential Advantages

REMS offers several potential benefits:

• No exposure to ionising radiation.
• Non-invasive and painless.
• Assesses the spine and hip, the most clinically important sites.
• Portable equipment that can be used in a wider range of healthcare settings.
• Suitable for repeated assessments when clinically appropriate.
• May be particularly helpful when DXA is difficult to perform or interpret.

Understanding the Results

Like a DXA scan, REMS provides measurements that help estimate bone density and fracture risk. However, the results should always be interpreted alongside:

• Your age and sex.
• Previous fractures.
• Medical conditions.
• Current medications.
• Lifestyle and other osteoporosis risk factors.

No single test provides the complete picture.

Current Role

Although REMS is an exciting advance, DXA remains the internationally recognised reference standard for diagnosing osteoporosis and monitoring treatment in most clinical guidelines.

REMS is best viewed as a valuable addition to bone health assessment and is likely to play an increasingly important role as evidence and clinical experience continue to grow.

Looking Ahead

The future of osteoporosis assessment is unlikely to rely on one test alone.

Bone density, bone quality, blood biomarkers, fracture risk assessment, artificial intelligence and personalised clinical judgement are increasingly being combined to provide a more complete understanding of bone health.

Key Takeaway

REMS is an innovative, radiation-free technology that is expanding the ways we can assess bone health. While DXA remains the current gold standard, REMS represents an exciting step towards more accessible and personalised osteoporosis assessment.

Next Step

In the next lesson, we'll explore bone turnover markers—blood tests that provide insight into how actively your bones are being broken down and rebuilt.

Why this matters

Bone density tells us how much bone you have.

Bone turnover markers tell us how active your bones are.

Together, they provide a more complete picture of bone health.

The Bigger Picture

Your bones are living tissue that is constantly being broken down and rebuilt. This natural process is known as bone remodelling.

Normally, bone formation and bone resorption remain in balance. However, in osteoporosis this balance is disrupted, causing bone to be lost faster than it is replaced.

Bone turnover markers are blood or urine tests that help measure these processes.

What do bone turnover markers measure?

There are two main types:

Bone resorption markers

These indicate how quickly bone is being broken down. One of the most commonly used is CTX (C-terminal telopeptide).

Bone formation markers

These indicate how quickly new bone is being formed. A commonly used marker is P1NP (Procollagen Type I N-Terminal Propeptide).

How are they used?

Bone turnover markers can help your healthcare professional to:

• Assess how active your bone remodelling is.
• Monitor your response to osteoporosis treatment.
• Confirm that medication is having the desired effect.
• Support long-term management alongside bone density measurements.

Changes in bone turnover markers are often seen within weeks or months, whereas changes in bone density usually take one to two years to become measurable.

Important to remember

Key Takeaway

Bone turnover markers provide an early indication of how your bones are responding. They are particularly valuable for monitoring treatment and helping your healthcare professional tailor your care over time.

Next Step

You have now explored the main methods used to assess bone health. In the next section, we'll look at the treatment options available and how lifestyle and medical approaches work together to reduce fracture risk.

Next course: Calcium — Its Role in Bone Strength →

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Written by Dr Taher Mahmud of the London Osteoporosis Clinic.
Provided for education and not a substitute for personalised medical advice.