Most people don't know they have osteoporosis until a bone breaks

Osteoporosis often causes no symptoms in its early stages, so you may not realize your bones are weakening. Many people discover they have it only after a fall results in a fracture—sometimes from something as minor as a stumble or a bump. This is why screening matters: a simple test can detect bone loss before a break happens.

The main way doctors find osteoporosis is through a bone density scan, usually called a DXA scan or DEXA scan (the letters stand for dual-energy X-ray absorptiometry). This test measures how much mineral is packed into your bones and compares your results to a healthy young adult's bones. It takes about 10 to 30 minutes, involves no needles, and uses a very small amount of radiation—less than you'd get from a cross-country flight.

Key Takeaways

  • A DXA scan is the standard test for osteoporosis and measures bone density by comparing your bones to a healthy young adult's baseline.
  • Your results come back as a T-score: a score of -2.5 or lower means osteoporosis, between -1 and -2.5 means low bone density, and above -1 is normal.
  • Doctors often recommend screening if you are a woman over 65, a man over 70, or younger if you have risk factors like a family history of fractures or use certain medications.
  • A fracture from a minor fall or bump can be the first sign of osteoporosis, even without prior screening.

Understanding your DXA scan results

When you get your DXA results, the report includes a number called a T-score. This score tells you how your bone density compares to that of a healthy 30-year-old. The score is measured in standard deviations—a statistical way of showing how far your result is from the average.

Here's what the numbers mean:

  • T-score of -1.0 or higher: Normal bone density.
  • T-score between -1.0 and -2.5: Low bone density, sometimes called osteopenia. Your bones are weaker than normal but not yet at the fracture threshold.
  • T-score of -2.5 or lower: Osteoporosis. Your bones are significantly weaker and fracture risk is higher.

Your doctor will also look at where the scan was done—the hip, spine, and forearm are the most common sites. A low score in any of these areas matters, but hip fractures are the most serious, so doctors pay close attention to hip density.

Who should get screened and when

Not everyone needs a DXA scan. Screening recommendations depend on your age, sex, and risk factors. The major medical organizations—including the U.S. Preventive Services Task Force—suggest different starting points for different groups.

Women should have a DXA scan starting at age 65, or earlier if they have risk factors. Men should start at age 70, or earlier if they have risk factors. Risk factors that lower the screening age include a family history of hip fractures, current smoking, heavy alcohol use, long-term use of corticosteroid medications (like prednisone), rheumatoid arthritis, or a previous fracture from a minor fall.

If your first scan shows normal bone density, you may not need another for 10 years. If it shows low bone density, your doctor will recommend repeat scans every 1 to 2 years to track whether your bones are staying stable or getting weaker.

Other signs that might prompt a scan

Even if you haven't reached the standard screening age, your doctor may order a DXA scan if you have certain conditions or symptoms. A sudden loss of height—more than an inch or two over a few years—can signal spine fractures from osteoporosis. A stooped posture or rounded upper back (sometimes called kyphosis) is another clue.

Certain medical conditions raise your risk: chronic kidney disease, celiac disease, inflammatory bowel disease, rheumatoid arthritis, and hormonal disorders like hyperthyroidism all affect bone density. Some medications do too, particularly long-term corticosteroids, some seizure medications, and certain cancer treatments. If you take any of these, mention it to your doctor even if you have no symptoms.

A fracture from a minor injury—a fall from standing height, a bump, or even a sudden sneeze—is a red flag. These "fragility fractures" often mean your bones are already weak, and a DXA scan should follow to confirm osteoporosis and guide treatment.

What happens after diagnosis

If your DXA results show osteoporosis, your doctor will discuss treatment options with you. The goal is to slow bone loss and reduce fracture risk. Treatment usually starts with lifestyle changes: getting enough calcium and vitamin D, doing weight-bearing exercise like walking or strength training, and stopping smoking if you smoke.

Many people also take medication. The most common class is called bisphosphonates—drugs like alendronate (Fosamax) or risedronate (Actonel) that slow the rate at which your body breaks down bone. Other medications work differently, such as denosumab (Prolia), which blocks a protein that triggers bone loss, or teriparatide (Forteo), which stimulates new bone formation. Your doctor will choose based on your bone density score, fracture risk, and other health conditions.

After starting treatment, you'll have follow-up DXA scans—usually every 2 years—to see whether your bone density is stable or improving. This helps your doctor know whether your current treatment is working or needs adjustment.

What a DXA scan does and doesn't show

A DXA scan is excellent at measuring bone density, but it doesn't show bone quality or structure. Two people with the same T-score might have different fracture risks because bone quality varies. Your doctor may also calculate your 10-year fracture risk using a tool called FRAX, which combines your DXA results with other factors like age, weight, smoking status, and alcohol use to give a more complete picture.

The scan also doesn't hurt and has no recovery time—you can go back to your normal day immediately. You don't need to fast or prepare in any special way, though you should remove metal objects like jewelry or belt buckles before the test.

Frequently Asked Questions

Can you feel osteoporosis before you break a bone?

Usually no. Osteoporosis itself causes no pain or other symptoms in early stages. Some people notice gradual height loss or a change in posture, but many have no warning signs at all. This is why screening is important—it finds the condition before a fracture happens.

How often do you need a DXA scan?

If your bone density is normal, you may not need another scan for 10 years. If you have low bone density or osteoporosis, your doctor will typically recommend repeat scans every 1 to 2 years to track changes and see how well treatment is working.

Is a DXA scan safe?

Yes. The radiation dose is very small—about one-tenth of a chest X-ray. The test is painless, takes 10 to 30 minutes, and has no side effects. You can have it done as often as your doctor recommends without concern.

What if your T-score is between -1 and -2.5?

This range is called low bone density or osteopenia. Your bones are weaker than normal but not yet at the osteoporosis threshold. Your doctor will discuss whether you need medication or whether lifestyle changes like exercise, calcium, and vitamin D are enough. Repeat scans help track whether your density is staying stable.

Can osteoporosis be reversed?

Osteoporosis cannot be completely reversed, but treatment can slow bone loss and sometimes increase bone density slightly. The goal is to stabilize your bones and reduce fracture risk. Starting treatment early and staying consistent with medication and lifestyle changes gives the best results.