Diagnosing Osteoporosis

Men and women over 60-years-old are at higher risk of osteoporosis than younger people. Nevertheless, it is possible to have osteopenia (low bone mass) or osteoporosis at a much earlier age. As osteoporosis has no obvious symptoms, it's important to go to your doctor if any risk factors apply to you.

By making positive lifestyle changes and following appropriate treatment strategies in consultation with a doctor, osteoporotic fractures can be prevented. Your doctor will take a thorough medical history that includes information on any recent fractures and may determine the next step is to have a bone mineral density (BMD) test.

 

 

 

 

 

 

 

 

 


What is a BMD test?

Traditional X-rays can’t measure bone density, but they can identify spine fractures. Bone mineral density (BMD) has to be measured by more specialised techniques. A number of different types of BMD tests are available, but the most commonly used is DXA (dual-energy X-ray absorptiometry)

DXA is a low radiation X-ray capable of detecting quite small percentages of bone loss. It is used to measure spine and hip bone density, and can also measure bone density of the whole skeleton. There are a number of different types of test options [1]:

  • DXA (peripheral DXA) measures bone mass at the forearm, finger and heel
  • SXA (single-energy X-ray absorptiometry) measures the heel or wrist
  • DPA (dual photon absorptiometry) measures the spine, hip or total body
  • SPA (single photon absorptiometry) measures the wrist
  • QCT (Quantitative Computed Tomography) measures the spine or hip
  • PQCT (peripheral QCT) measures the forearm
  • QUS (Quantitative Ultrasound) uses sound waves to measurethe heel or finger

A DXA scan, which is used to measure spine and hip bone density, is the most common technique for assessing the risk of osteoporosis.

What do my test results mean?

The World Health Organization has defined a number of threshold values (measurements) for osteoporosis. The reference measurement is derived from bone density measurements in a population of healthy young adults (called a T-score). Osteoporosis is diagnosed when a person’s BMD is equal to or more than 2.5 standard deviations below this reference measurement [2].

Osteopenia is diagnosed when the measurement is between 1 and 2.5 standard deviations below the young adult reference measurement.

Status Hip BMD
Normal T-score of -1 or above
Osteopenia T-score lower than -1 and greater than -2.5
Osteoporosis T-score of -2.5 or lower
Severe osteoporosis T-score of -2.5 or lower, and presence of at least one fragility fracture


If the results of your BMD test show osteopenia or osteoporosis, it does not automatically mean that you will have a fracture. There are lifestyle changes and a number of available therapies that your doctor might prescribe to slow down bone loss and help prevent fractures.

How else do they diagnose osteoporosis?

There are a number of other methods for diagnosing osteoporosis that have been used extensively in clinical trials and epidemiological studies. These include radiological assessments and Bone Turnover Markers (BTM). Read more information on these methods of diagnosis

References:

1. World Health Organisation. Assessment of fracture risk and its implication to screening for postmenopausal osteoporosis: Technical report series 843. Geneva: WHO,1994
2. Kanis J. Diagnosis of osteoporosis and assessment of fracture risk. Lancet 2002;359:1929-36