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.
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.
In this Article
- Osteoporosis facts
- What is osteoporosis?
- What are osteoporosis symptoms and signs?
- What are the consequences of osteoporosis?
- Why is osteoporosis an important public-health issue?
- What factors determine bone strength?
- What are osteoporosis risk factors and causes?
- How is osteoporosis diagnosed?
- Who should have bone density testing?
- What is the treatment for osteoporosis, and can osteoporosis be prevented?
- Exercise, quitting cigarettes, and curtailing alcohol
- Calcium supplements
- Vitamin D
- Hormone therapy (menopausal hormone therapy)
- Medications that prevent bone loss and breakdown
- Choosing an osteoporosis medication
- Prevention of osteoporosis due to long-term corticosteroids
- Monitoring osteoporosis therapy
- Prevention of hip fractures in elderly people with osteoporosis
- What are complications of osteoporosis?
- What is the prognosis (outlook) for patients with osteoporosis?
- Osteoporosis FAQs
- Find a local Internist in your town
How is osteoporosis diagnosed?
A routine X-ray can reveal osteoporosis of the bone because the bones appear much thinner and lighter than normal bones. Unfortunately, by the time X-rays can detect osteoporosis, at least 30% of the bone has already been lost. In addition, X-rays are not accurate indicators of bone density. Thus, the appearance of the bone on X-ray often is affected by variations in the degree of exposure of the X-ray film.
The National Osteoporosis Foundation, the American Medical Association, and other major medical organizations recommend a dual-energy X-ray absorptiometry scan (DXA, formerly known as DEXA) be used for the diagnosis of osteoporosis. DXA typically measures bone density in the hip, the spine, and the forearm. The test takes only five to 15 minutes to perform, exposes patients to very little radiation (less than one-tenth to one-hundredth of the amount used on a standard chest X-ray), and is quite precise.
The bone density of the patient is compared to the average peak bone density of young adults of the same sex and race. This score is called the "T score," and it expresses the bone density in terms of the number of standard deviations (SD) below peak young adult bone mass.
- Osteoporosis is defined as a bone density T score of -2.5 or below.
- Osteopenia (between normal and osteoporosis) is defined as bone density T score between -1 and -2.5.
It is important to note that while osteopenia is considered a lesser degree of bone loss than osteoporosis, it nevertheless can be of concern when it is associated with other risk factors (such as smoking, cortisone steroid usage, rheumatoid arthritis, family history of osteoporosis, etc.) that can increase the chances for developing vertebral, hip, and other fractures. In this setting, osteopenia may require medication as part of the treatment program.
Who should have bone density testing?
The National Osteoporosis Foundation guidelines state that there are several groups of people who should consider DXA testing:
- All postmenopausal women below age 65 who have risk factors for osteoporosis
- All women aged 65 and older
- Postmenopausal women with fractures, although this is not mandatory because treatment may well be started regardless of bone density
- Women with any of more than 50 medical conditions associated with osteoporosis; a primary-care physician can scan a patient's list of medical illnesses to determine if one of these conditions is present (see causes above)
- Women whose decision to begin treatment for osteoporosis might be aided by bone density testing to determine the presence or absence of osteoporosis or osteopenia
The National Osteoporosis Foundation guidelines state that bone-density testing does not need to be performed if a person has a known osteoporotic fracture because the patient will be treated for osteoporosis with or without a bone-density study. In addition, bone-density testing is not appropriate if the person undergoing the test is not willing to take treatment based on the results. Therefore, if bone-density testing is done, it should be performed on people willing to take some specific action based on the results.
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