Osteoporosis: Stop the bone robber’
Your next patient is a 52-year-old Caucasian whose daily diet consists primarily of fast-food items and diet caffeinated sodas. She smokes 10 to 12 cigarettes per day, drinks two to three alcoholic beverages per day, and leads a sedentary lifestyle. Is she at risk for osteoporosis?
Yes, and she is not alone, according to statistics from the National Institutes of Health (NIH) in Bethesda, MD.1 About 10 million people in the United States have osteoporosis, which makes it the most prevalent metabolic bone disorder in this country. An additional 18 million individuals already have low bone mass, which places them at increased risk for this disorder.
National and international experts recently gathered at the NIH-coordinated Consensus Conference on Osteoporosis to discuss the latest research findings on osteoporosis. The second such event in 16 years, the conference focused on prevention, diagnosis, and therapy for the skeletal disorder, which is characterized by compromised bone strength predisposing to an increased risk of fracture.
"The conference showed that we have made a lot of progress," notes Conrad Johnston, MD, professor of medicine at Indiana University School of Medicine in Indianapolis and president of the National Osteoporosis Foundation in Washington, DC, a nonprofit, voluntary health organization dedicated to reducing the widespread prevalence of osteoporosis. "As usual, as you learn new things, there are new questions that arise," Johnston says.
Calcium is the specific nutrient most important for attaining peak bone mass and for preventing and treating osteoporosis, according to a statement issued by the consensus panel.2
Keep calcium intake in mind when working with adolescent patients: Only 10% of girls and 25% of boys between ages 9 and 17 obtain an adequate amount of calcium — 1,300 mg per day — in their diet through the consumption of dairy products and vegetables.2 Most adults should get 1,000 mg per day of total elemental calcium intake, or 1,500 mg for post-menopausal women not taking supplemental estrogen.3
Help patients boost calcium intake by including low-fat dairy products such as milk, yogurt, and cheese; dark green leafy vegetables such as broccoli, spinach, and collards; tofu; and almonds.4 Remember to also discuss vitamin D intake, which is required for optimal calcium absorption. A daily intake of 400 to 600 IU has been established for adults.2
There is strong evidence that physical activity early in life contributes to higher peak bone mass, according to the findings issued by the NIH consensus panel.2 Since exercise not only improves bone health, but increases muscle strength, coordination, and balance, it is an important part of an osteoporosis prevention program at any age.4
Evaluate estrogen’s role
Although hormone replacement therapy remains a common treatment and prevention option in osteoporosis, more information is needed on how estrogen alone or in combination with other treatments reduces the incidence of fractures.
"I think one of the important points that came out of the conference is that, although we do have some information on estrogen, and we certainly have information on the efficacy of the bisphosphonates, particularly in terms of bone density, what we don’t really have are long-term studies which can assess these particular therapies individually or in combination head to head," notes Anne Klibanski, MD, professor of medicine at Harvard Medical School in Boston and chair of the NIH consensus panel.
Reduction in estrogen production with menopause is the major cause of loss of bone mineral density during later life.2 Estrogen is used to prevent osteoporosis in women who are at high risk for developing the disease, and it also is used to treat the disease after it has been diagnosed.3
Prevention and treatment alternatives to estrogen include the selective estrogen receptor modulator raloxifene (Evista, manufactured by Eli Lilly and Co. of Indianapolis) and the bisphosphonate alendronate sodium (Fosamax, manufactured by Merck & Co. of West Point, PA). Calcitonin (Miacalcin, manufactured by Novartis Pharmaceuticals, East Hanover, NJ) carries an indication for treatment of the disease. Another bisphosphonate, risedronate, has been shown to be effective in reduc- ing nonhip-fracture risks in post-menopausal women.5 The drug, marketed in the United States as Actonel by Procter & Gamble Pharmaceuticals of Cincinnati, currently is indicated for treatment of Paget’s disease and does not carry a U.S. indication for prevention/treatment of osteoporosis.
The most commonly used measurement to diagnose osteoporosis and predict fracture risk is based on bone mineral density (BMD).2 The World Health Organization in Geneva, Switzerland, has selected BMD measurements to establish criteria for diagnosing osteoporosis, expressed through a T-score, which is the number of standard deviations (SD) above or below the average BMD value. Osteoporosis is present when the T-score is at least minus 2.5 SD.
New technologies have improved the detection of loss of bone mineral. Dual energy X-ray absorptiometry (DXA) is the standard for measuring bone mineral density of the hip. Other measures of bone strength, such as ultrasound of the heel, are as effective in predicting hip fracture. However, the NIH panel recognized that no standard exists for comparing different devices and recommended collecting data necessary to establish testing guidelines for osteoporosis.
"I think that one of the things that the bone community and all physicians are grappling with is how do you standardize different measurements?" asks Klibanski. "One way, among many suggested, is to put a clinical trial into place to assess different therapies and different comparisons of therapies."
References
1. Bowersox J, Wortman J. NIH Consensus Panel Addresses Osteoporosis Prevention, Diagnosis, and Therapy. Bethesda, MD: National Institutes of Health; March 29, 2000.
2. Osteoporosis Prevention, Diagnosis, and Therapy. NIH Consensus Statement 2000; 17(2).
3. North American Menopause Society. Preventing Osteoporosis: The Bone Robber. Cleveland; 1997.
4. National Institutes of Health. Osteoporosis and Related Bone Diseases National Resource Center. Osteoporosis Overview. Web: www.osteo.org/osteo.html.
5. Harris ST, Watts NB, Genant HK, et al. Effects of risedronate treatment on vertebral and nonvertebral fractures in women with post-menopausal osteoporosis: A randomized controlled trial. JAMA 1999; 282:1,344-1,352.
• National Osteoporosis Foundation, 1232 22nd St. N.W., Washington, DC 20037-1292. Telephone: (202) 223-2226. Web: www.nof.org.
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