Osteopenia is defined as low bone density caused by bone loss. Osteopenia is often a precursor to osteoporosis, a common condition of brittle bones that can result in fracture. The two medical terms are sometimes confused and it's important to know the difference and how each is related to arthritis.
The biggest difference between osteopenia and osteoporosis is that osteopenia is not considered a disease while osteoporosis is. Instead, osteopenia is considered a marker for risk of fractures.
Osteopenia results when the formation of new bone does not occur at a rate which can offset normal bone loss. Bone density scans have made this easier to measure. Prior to bone density testing, radiologists used the term osteopenia to describe bones that seemed more translucent than normal on x-ray, and the term osteoporosis described the occurrence of vertebral fracture.
Bone mineral densitometry, or bone density scans, changed those definitions. According to the World Health Organization, osteoporosis is defined as a T score of -2.5 or lower and osteopenia is defined as a T score higher than -2.5 but lower than -1.0. A T score above -1 is normal. The T score is your bone density compared with what is normally expected in a healthy young adult of your sex. Using this criteria, 33.6 million Americans have osteopenia. The significance of that statistic is similar to identifying who is pre-hypertensive or those who have borderline cholesterol -- in other words, identifying a group that is at risk for developing a disease.
Other Risk Factors for Fracture
Osteopenia is only one risk factor for fracture. Other risk factors include:
- previous fracture
- age (risk of fracture increases with age)
- smoking (weakens bones)
- drinking more than 2 alcoholic drinks per day (increases risk of hip fracture)
- low body weight (increases risk of hip fracture)
- race and gender (white women have 2 or 3 times risk compared to men or black and Hispanic women)
- having a parent who had a hip fracture
- sedentary lifestyle
- inadequate calcium and vitamin D intake
- conditions that increase the risk of falling such as poor vision, poor footwear, medical conditions that affect balance, use of sedative medications, or a history of falls
- taking certain medications, including corticosteroids can result in glucocorticoid-induced osteoporosis
- having certain medical conditions, such as rheumatoid arthritis or other rheumatic diseases can cause secondary osteoporosis
Secondary osteoporosis occurs when an underlying disease, deficiency, or drug causes osteoporosis. When no secondary cause can be identified, the condition is referred to as primary osteoporosis.
Lifestyle changes can slow the progression of bone loss and decrease the risk of fractures. Lifestyle changes that can help prevent fractures include:
- maintaining a healthy weight
- participating in regular exercise, including weightbearing exercise (walking, running, hiking, tennis are examples of weightbearing exercise while swimming is non-weightbearing)
- making sure you have enough vitamin D and calcium in your diet or by taking dietary supplements
- no smoking
Having regular bone density tests can help slow progression of bone loss and decrease the risk of fractures by monitoring bone density measurements. The U.S. Preventive Services Task Force (USPSTF) found good evidence that bone density measurements accurately predict the risk for fractures in the short-term and formulated these recommendations for osteoporosis screening.
Treatment With Osteoporosis Medications
Medications are used to treat osteoporosis -- but doctors (rheumatologists, gynecologists, internal medicine doctors, and geriatric specialists) who treat patients showing signs of early bone loss don't always agree on the best course. Should patients with osteopenia be treated with medications to prevent progression to osteoporosis?
The National Osteoporosis Foundation, the American Association of Clinical Endocrinologists, and the North American Menopause Society recommend that patients with osteoporosis or fracture should be treated but there is inconsistency in what is recommended for people with osteopenia. Is treating osteopenia necessary or even cost-effective?
Many experts believe that treating osteopenia with medications would not be cost-effective. With additional risk factors, such as corticosteroid use or having rheumatoid arthritis, treating osteopenia becomes more of a consideration though.
It's important to remember that T scores alone cannot predict which patients with osteopenia will have fractures and which patients will not. Assessing all of the risk factors is the best way to decide whether treatment with osteoporosis medications is indicated. Patients with signs of early bone loss should focus on lifestyle modifications and discuss the benefits and risks of osteoporosis medications with their doctor.
Osteopenia and Preventing Fractures. Torpy MD, Janet M. The Journal of the American Medical Association. December 6, 2006.
Clinician's Corner. A 55-Year-Old Woman With Osteopenia. Cummings MD, Steven R. The Journal of the American Medical Association. December 6, 2006.
Osteopenia. Khosla MD, Sundeep. et al. The New England Journal of Medicine. May 31, 2007.
Does Early Bone Loss Mean You Need Drugs? Payne, January W. U.S. News and World Report. January 30, 2008.