Each year in the U.S., osteoporosis causes some 700,000 spinal fractures and 300,000 hip fractures, a leading cause of nursing-home admissions. Women, who lose bone rapidly at menopause, are far more susceptible than men. An estimated 50% of women and 25% of men over age 50 will suffer an osteoporosis-related fracture in their lifetime.
The incidence of hip fractures has dropped by about 30% since 1995 when Fosamax, the first bisphosphonate, went on sale in the U.S. But curiously, the decline in hip fractures has continued, even with fewer Americans taking the drugs in recent years.
There are many possible explanations: fewer Americans are smoking (which hastens bone loss); more are exercising (which helps build bone) and more are obese (which helps guard against fractures).
Jennifer Schneider, a Tucson, Ariz., physician, was 59 years old and had taken bisphosphonates for seven years when her thigh bone suddenly snapped on the subway while visiting New York City in 200.X-rays showed her femur—usually one of the strongest bones in the body—had broken in two just below the hip. Surgeons inserted a titanium rod to hold the bone together, but the fracture was slow to heal and required a second surgery.
In a published study of 81 cases, Dr. Schneider found that, after the first fracture, 40% of the women suffered a similar break in the other leg within two years, and 35% had delayed healing.
One theory is that prolonged use of the drugs may slow the turnover of bone too much in some people, leaving it unusually brittle. Estimates of how common these fracture are range from 1 in 100,000 to 1 in 500 among women who have used bisphosphonates for five years or more.
For its part, the FDA has told doctors and patients to be aware of the potential for typical femur fractures and jaw problems and urged caution about long-term use of the drugs, but has not issued specific recommendations about when to stop or for how long.
Women should have a baseline bone density scan at least by age 65, and earlier if they have a strong family history of osteoporosis and other risk factors. A score of minus 2.5 indicates osteoporosis, but treatment should not be based on that alone, doctors now say.
An online tool, known as FRAX, for Fracture Risk Assessment Tool, developed by the World Health Organization, takes into account other factors such as a patient’s age, gender, weight, height, smoking, alcohol consumption and parental hip fractures. It computes the chances of suffering a major bone fracture in the next 10 years. The National Osteoporosis Foundation says if the risk is more than 3% for a hip fracture or 20% for other major fractures, the advantages of treatment outweigh the risks.
Doctors continue to recommend 1000 to 1500 mg of calcium, 600 to 800 IUs of vitamin D and at least 30 minutes of weight-bearing exercise, three times a week. Whether that alone is sufficient to prevent osteoporosis in some patients isn’t clear, but some think it’s the safest course.
For more information on osteoporosis, go to: http://www.build-better-bones.com