DXA (dual-energy X-ray absorptiometry) scans are an imaging test that uses low-dose X-rays to evaluate a person's bone health. Dr. Michael Perry, an associate professor of radiology and medical imaging at the University of Virginia's school of medicine, explains that these scans primarily measure the strength and mineral content of bones. This information helps determine an individual's risk of osteoporosis and bone fractures.
The National Institute on Aging highlights the importance of this information, noting that broken bones in older adults can be a precursor to more serious health issues and potentially lead to long-term disability. Dr. Ann Malbas, an endocrinologist at the Mayo Clinic, describes DXA scans as "safe, quick and painless," typically taking 10-20 minutes to complete.
While important for people in their 60s and above, DXA scans are also increasingly used by younger individuals interested in body composition. Dr. Malbas notes that these scans can estimate fat percentage, muscle mass, and where fat is distributed throughout the body. However, Dr. Shadpour Demehri, a professor of radiology at Johns Hopkins University, states that routine DXA scans are generally not essential for most young people as they are "unlikely to provide information that changes medical care."
DXA scans are recommended for women aged 65 and older, men aged 70 and older, and younger adults with specific risk factors. These risk factors can include a history of broken bones from minor falls, long-term use of steroid medications, a family history of osteoporosis or hip fractures, and certain medical conditions like COPD. Pregnancy is generally considered a reason to postpone the examination due to the involvement of ionizing radiation.