‘Safe, quick and painless’: what is a DXA scan, and do you need one for bone health?

A DXA scan, also known as a DEXA scan, is an imaging test that employs low-dose X-rays to assess a person's bone health. Its primary purpose is to evaluate bone mineral density, which aids in determining the likelihood of osteoporosis and bone fractures. Dr Michael Perry, a radiology professor at the University of Virginia, explains that DXA scans are most commonly utilized for individuals aged 60 and above, as well as for younger adults with elevated risk factors.

The scan involves a person lying down on a padded table while a scanning arm passes over their body. Two low-dose X-ray beams measure the mineral content in the bones, specifically targeting the hip and spine regions. The entire procedure typically takes between 10 to 20 minutes. While the primary focus is bone mineral density, DXA scans can also measure body composition, including fat percentage, muscle mass, and the distribution of fat throughout the body.

Dr Ann Malbas, an endocrinologist at the Mayo Clinic, explains that DXA scans are considered safe, quick, and painless.

Typically, DXA scans are recommended for women over 65 and men aged 70 and above. Additionally, younger adults with significant risk factors, such as a history of bone fractures from minor injuries, long-term steroid use, a family history of osteoporosis, or specific medical conditions like COPD, may benefit from regular scans. Osteoporosis is often referred to as a "silent disease" as most individuals remain unaware of their condition until they experience a fracture.

According to Dr Shadpour Demehri, a radiology professor at Johns Hopkins University, osteoporotic fractures affect one in three women and one in five men over the age of 50.

Regular DXA scans are crucial for high-risk populations, as early detection is vital due to the often asymptomatic nature of osteoporosis. The scans are generally deemed safe, although Demehri advises postponing the examination during pregnancy due to the involvement of ionizing radiation. People who have undergone imaging tests with contrast materials, such as barium studies, may need to wait before getting a DXA scan to ensure accurate results.

For those interested in monitoring their body composition, DXA scans offer a precise assessment of health beyond just weight measurements. Dr Perry highlights that while weight is commonly associated with health, it does not differentiate between muscle and fat. DXA scans provide a more comprehensive understanding of one's overall health.

While routine DXA scans are not necessary for most young individuals, maintaining a healthy lifestyle through regular exercise, a balanced diet, and appropriate weight management remains essential for everyone.