What is a Bone Density Test? Purpose, Procedure & Results

A bone density test measures how strong your bones are by checking how much calcium and other minerals they contain. This simple, painless scan helps your doctor understand if your bones are getting weaker over time or if you're at risk for fractures. Think of it as a health check-up specifically designed for your skeleton.

What is a bone density test?

A bone density test, also called a DEXA scan or DXA scan, uses low-energy X-rays to measure the density of minerals in your bones. The test focuses on areas where fractures happen most often, like your spine, hip, and sometimes your forearm. It's completely different from a regular X-ray because it can detect bone loss before you actually break a bone.

The test gives your doctor a clear picture of your bone health by comparing your bone density to that of a healthy young adult. This comparison helps identify conditions like osteoporosis, which makes bones fragile and more likely to break. Most people find the test surprisingly quick and comfortable.

Why is a bone density test done?

Your doctor might recommend a bone density test to check if you're losing bone mass or to monitor a condition that affects your bones. This test is especially important for catching osteoporosis early, before you experience a painful fracture. Early detection means you can take steps to protect your bones and prevent future problems.

The test is also used to track how well bone treatments are working if you're already being treated for bone loss. Your doctor can compare results over time to see if your bones are getting stronger, staying stable, or continuing to weaken. This information helps them adjust your treatment plan if needed.

Sometimes doctors order this test if you've had fractures that seemed to happen too easily, or if you have risk factors that make bone loss more likely. It's a valuable tool for understanding your individual bone health story.

What is the procedure for a bone density test?

The bone density test procedure is straightforward and typically takes about 10 to 30 minutes. You'll lie on a padded table while a scanning arm passes over your body, taking pictures of your bones. The machine makes some noise, but it's not loud or uncomfortable like some other medical scans.

During the scan, you'll need to stay very still while the machine takes measurements of specific areas. The technologist will position you carefully and may use foam blocks or straps to help you maintain the right position. You won't feel anything during the actual scanning process.

The X-ray dose used in this test is extremely low, much less than a chest X-ray. You'll be able to breathe normally throughout the procedure, and there's no need for any injections or contrast materials. Most people find it relaxing and much easier than they expected.

How to prepare for your bone density test?

Preparing for your bone density test is quite simple, but there are a few important steps to follow. You should avoid taking calcium supplements for at least 24 hours before your test, as they can interfere with the accuracy of your results. This includes calcium-containing antacids and multivitamins with calcium.

Wear comfortable, loose-fitting clothes without metal buttons, zippers, or belt buckles that might show up on the scan. You may be asked to change into a hospital gown if your clothing has metal parts. Remove jewelry, watches, and any metal objects from the areas being scanned.

Let your doctor know if you've had any recent barium exams or CT scans with contrast material, as these can affect your bone density results. You should also mention if you might be pregnant, even though the radiation exposure is minimal. If you've had previous bone density tests, bring those results with you for comparison.

How to read your bone density test results?

Your bone density test results come with two important numbers called T-scores and Z-scores. The T-score compares your bone density to that of a healthy 30-year-old adult of the same sex. A T-score of -1.0 or higher means your bones are normal, while -1.0 to -2.5 indicates low bone mass, and -2.5 or lower suggests osteoporosis.

The Z-score compares your bone density to other people of your same age, sex, and ethnicity. This score helps your doctor understand if your bone density is appropriate for someone your age or if it's unusually low. A Z-score of -2.0 or lower might indicate that something other than aging is causing bone loss.

Your doctor will explain these numbers in the context of your overall health, medical history, and risk factors. They'll also consider factors like your family history, lifestyle, and any medications you're taking that might affect bone health. The results help create a personalized plan for keeping your bones as healthy as possible.

How to improve your bone density?

Improving your bone density involves a combination of lifestyle changes and, sometimes, medication. Weight-bearing exercises like walking, dancing, or strength training can help stimulate bone formation and slow bone loss. Your bones respond to the stress of exercise by becoming stronger over time.

Getting enough calcium and vitamin D is crucial for bone health. Most adults need about 1,000 to 1,200 mg of calcium daily and 800 to 1,000 IU of vitamin D. You can get these nutrients from foods like dairy products, leafy greens, and fortified foods, or through supplements if your doctor recommends them.

Lifestyle factors play a significant role in bone health. Quitting smoking and limiting alcohol consumption can help prevent further bone loss. Smoking interferes with calcium absorption and reduces bone formation, while excessive alcohol can interfere with your body's ability to absorb calcium and affect hormone levels that regulate bone health.

If lifestyle changes aren't enough, your doctor might prescribe medications specifically designed to strengthen bones. These medications work in different ways - some slow down bone breakdown while others stimulate new bone formation. Your doctor will choose the best option based on your specific situation and health needs.

What is the best bone density level?

The best bone density level is one that falls within the normal range for your age and keeps you at low risk for fractures. For most people, a T-score of -1.0 or higher is considered optimal. However, what's "best" for you depends on your individual circumstances, including your age, overall health, and risk factors.

As we age, some bone density loss is natural and expected. The goal isn't necessarily to have the bone density of a 20-year-old, but rather to maintain density that's appropriate for your age and reduces your fracture risk. Your doctor considers your whole health picture when determining what bone density level is ideal for you.

Prevention is always better than treatment when it comes to bone health. Maintaining good bone density throughout your life by staying active, eating well, and avoiding harmful habits gives you the best chance of keeping strong bones as you age. Regular monitoring helps catch any changes early so you can take action if needed.

What are the risk factors for low bone density?

Several factors can increase your risk of developing low bone density, and understanding these helps you take preventive steps. Age is the most significant risk factor, as bone density naturally decreases after age 30, with more rapid loss occurring after menopause in women due to declining estrogen levels.

Here are the main risk factors that can contribute to low bone density:

• Being female, especially after menopause
• Advanced age (over 50)
• Small, thin body frame
• Family history of osteoporosis or fractures
• Caucasian or Asian ethnicity
• Low calcium and vitamin D intake
• Sedentary lifestyle or lack of weight-bearing exercise
• Smoking tobacco
• Excessive alcohol consumption
• Certain medications like steroids, antacids, or blood thinners
• Medical conditions such as rheumatoid arthritis, celiac disease, or hyperthyroidism
• Eating disorders that affect nutrition
• Early menopause or surgical removal of ovaries

Some risk factors, like age and genetics, can't be changed, but many others are within your control. Recognizing your risk factors helps you and your doctor develop a plan to protect your bone health and determine how often you need bone density testing.

Is it better to have high or low bone density?

Higher bone density is generally better than lower bone density because it means stronger bones that are less likely to break. However, extremely high bone density can sometimes indicate other health conditions, so the goal is to maintain bone density within a healthy range rather than pursuing the highest possible numbers.

Normal to slightly high bone density provides the best protection against fractures while indicating healthy bone metabolism. Your bones are constantly breaking down and rebuilding themselves, and good bone density shows this process is working well. Strong bones give you confidence to stay active and maintain your independence as you age.

Very low bone density significantly increases your fracture risk, even from minor falls or everyday activities. This can lead to serious complications, especially hip or spine fractures that can affect your mobility and quality of life. The goal is to maintain or improve bone density to stay within the healthy range for your age.

What are the possible complications of low bone density?

Low bone density can lead to several serious complications that affect your quality of life and independence. The most immediate concern is an increased risk of fractures, which can occur from minor falls or even normal activities like coughing or bending over. Hip fractures are particularly serious and can lead to long-term mobility problems.

Here are the main complications that can arise from low bone density:

• Increased fracture risk, especially in the hip, spine, and wrist
• Chronic pain from compression fractures in the spine
• Loss of height due to vertebral compression
• Stooped posture or hunched back
• Reduced mobility and independence
• Fear of falling, leading to decreased activity
• Social isolation due to limited mobility
• Depression and anxiety related to physical limitations
• Increased risk of disability
• Higher healthcare costs and hospitalizations

The good news is that many of these complications can be prevented or minimized with proper treatment and lifestyle changes. Early detection through bone density testing allows you to take action before serious complications develop. Working with your healthcare team to address low bone density can help you maintain your active lifestyle and independence.

What are the possible complications of high bone density?

While high bone density is generally healthier than low bone density, extremely high levels can sometimes indicate underlying health issues. Very high bone density might suggest conditions like osteopetrosis, a rare genetic disorder where bones become too dense and brittle, or other metabolic bone diseases that affect normal bone remodeling.

In rare cases, unusually high bone density can be associated with certain cancers that have spread to the bones or conditions that affect calcium metabolism. However, these situations are uncommon, and most people with high bone density readings are simply blessed with strong, healthy bones that provide excellent protection against fractures.

Some medications used to treat osteoporosis can occasionally lead to very high bone density readings over time. Your doctor will monitor your bone density levels if you're taking these medications to ensure they're working effectively without causing any complications. Regular follow-up testing helps maintain the right balance.

For most people, having high bone density is a positive sign that indicates good bone health and lower fracture risk. Your doctor will evaluate your results in the context of your overall health to determine if any follow-up is needed.

When should I see a doctor for bone density concerns?

You should see a doctor about bone density testing if you're a woman over 65 or a man over 70, as these are the standard screening ages recommended by medical organizations. However, you might need testing earlier if you have risk factors like a family history of osteoporosis, previous fractures, or certain medical conditions.

Consider scheduling a bone density test if you've experienced fractures that seemed to happen too easily, especially if you're over 50. A fracture from a fall from standing height or less could indicate weak bones that need evaluation. Don't wait for multiple fractures to occur before seeking medical attention.

Certain symptoms might suggest bone density issues and warrant medical evaluation. These include loss of height over time, developing a stooped posture, or experiencing back pain that could indicate compression fractures. While these symptoms can have other causes, they're worth discussing with your doctor.

If you're taking medications that can affect bone density, such as steroids or certain cancer treatments, your doctor should monitor your bone health regularly. Don't hesitate to bring up concerns about your bone health during routine medical visits, especially if your risk factors have changed.