Bone Density Scan (cont.)
Catherine Burt Driver, MD
Catherine Burt Driver, MD, is board certified in internal medicine and rheumatology by the American Board of Internal Medicine. Dr. Driver is a member of the American College of Rheumatology. She currently is in active practice in the field of rheumatology in Mission Viejo, Calif., where she is a partner in Mission Internal Medical Group.
William C. Shiel Jr., MD, FACP, FACR
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
In this Article
- Bone density scan facts
- What is osteoporosis?
- How does osteoporosis occur?
- What is bone mineral density (BMD)?
- Who invented the bone density scan?
- Who performs bone density scans?
- Where is a bone density test done?
- What information is on a DXA report?
- Why is bone mineral density measurement important?
- What is the relationship between BMD and fracture risk?
- Who should have BMD testing?
- How is BMD measured?
- What are other methods of measuring BMD?
- How often should DXA scans be repeated to monitor treatment?
- What is the cost of DXA?
- What about the accuracy of BMD testing in the doctor's office using smaller equipment?
- Find a local Rheumatologist in your town
Why is bone mineral density measurement important?
Determining a person's BMD helps a health care professional decide if a person is at increased risk for osteoporosis-related fracture. The purpose of BMD testing is to help predict the risk of future fracture so that the treatment program can be optimized. The information from a BMD is used to aid a decision as to whether nonprescription and/or prescription medicine therapy is needed to help reduce the risk of fracture. Additionally, if a patient has a fracture or is planning orthopedic surgery, a diagnosis of osteoporosis might affect the surgical plan. A fracture that could potentially heal in a cast with normal bone mass might require either a longer period of casting or even surgery if the patient has osteoporosis. Sometimes spinal surgeons treat patients with low bone density with bone building medication prior to surgery in order to improve the surgical outcome of bone that is operated on.
What is the relationship between BMD and fracture risk?
In patients with low bone mass at the hip or the spine (the two areas traditionally measured with DXA [formerly referred to as DEXA] scanning), there is a two- to threefold increase in the incidence of any osteoporotic fracture. In other words, low bone density at the measured areas of the spine and hip can even predict future osteoporotic fractures at other parts of the body besides the spine and hip. In subjects with a BMD in the osteoporosis range, there is approximately a five times increase in the occurrence of osteoporotic fractures.
Who should have BMD testing?
BMD testing is recommended for all women over the age of 65. Additionally, postmenopausal women under 65 years who have risk factors for osteoporosis other than menopause (these include a previous history of fractures, low body weight, cigarette smoking, and a family history of fractures) should be tested. Finally, men or women with strong risk factors as listed below should discuss the benefit of DXA scanning with their health care professional to see if testing is indicated.
The following are potential risk factors for osteoporosis that might suggest the need for DXA scanning:
- Personal history of fracture as an adult
- History of fracture in first-degree relative
- Low body weight or thin body stature
- Advanced age
- Current cigarette smoking
- Use of corticosteroid therapy for more than three months
- Impaired vision
- Estrogen deficiency at early age
- Poor health/frailty
- Recent falls
- Lifelong low calcium intake
- Low physical activity
- Alcohol intake of more than two drinks/day
- Thyroid disease
- Rheumatoid arthritis
- Excessive caffeine consumption
- Use of oral contraceptive (birth control pills)
Next: How is BMD measured?
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