Balancing Acts:
Weighing Treatment Benefits and the Risks of Osteoporosis

Researchers are finding that the increased incidence of secondary osteoporosis is no laughing matter as they discover more links between common medications and accelerated bone loss in older adults. Weighing the benefits of drugs to treat such diseases as depression, gastric reflux, and prostate cancer against the increased risk of secondary osteoporosis is yet another balancing act for physicians and families to manage as they care for the elderly.

Dr. Cathleen Colon-Emeric, a specialist in fracture prediction and prevention in older adults at the Duke University Medical Center , notes that “Secondary osteoporosis resulting from the use of certain medications is a very hot research topic. We have known for some time that age, bone density, and lifestyle choices place patients at a higher risk for osteoporosis. Now, when patients, especially men, are treated with certain medications to manage diseases unrelated to osteoporosis, we find they may need to be in a higher risk category.”

Secondary osteoporosis occurs when an underlying disease or drug causes accelerated bone loss. Although it is affecting both men and women at increasing rates, secondary osteoporosis is less frequently diagnosed and treated than primary osteoporosis, or age- associated bone loss. This is of special concern to healthcare professionals; adults with secondary osteoporosis have a two-to-three-fold higher risk of hip and vertebral fractures than do those with primary osteoporosis.

One of the reasons for lack of awareness about secondary osteoporosis is that it is common in men; until recently, most investigators targeted their research on women. The Journal of the American Academy of Orthopedic Surgeons reports that even though 50 percent of the causes of osteoporosis in men can be traced either to other diseases or to lifestyle choices, very few men see the disease as a threat to their mobility and independence.

Treating secondary osteoporosis is complex. Physicians who treat the primary illness now need to recognize and manage the increased risks of secondary osteoporosis. Older adults are also living longer and consequently undergoing treatment for their diseases for longer periods of time. This puts them at increased risk for fractures, over and above the risk they carry due to age. Antidepressants, acid suppressing drugs, and hormone manipulations are of particular interest to researchers because of their link to bone loss and their widespread and increasing use in older adults.

How are antidepressants linked to fracture risks?
Depression is common in older adults, affecting about 10 percent of the population. Antidepressants are the most frequently prescribed therapeutic class of drug; prescriptions for selective serotonin reuptake inhibitors (SSRIs) have soared by more than 30 percent between 2000 and 2004. New research by Dr. David Goltzman, Director of the Centre for Bone and Periodontal Research at McGill University in Montreal , shows that daily use of SSRIs, which include the commonly used drugs Prozac and Paxil, doubles the risk of bone fractures in adults 50 and older. Daily use of SSRIs was also associated with a 4 percent reduction in bone mineral density of the hip and 2.4 percent of the lower spine. Further studies are underway.

Are heartburn medications associated with osteoporosis?
Widely used acid suppressing drugs, known as proton pump inhibitors, are also the subject of recent osteoporosis research. Researcher Yu-Xiao Yang, MD, from the University of Pennsylvania School of Medicine in Philadelphia found that people over age 50 taking proton pump inhibitors, which include such drugs as Prilosec, Nexium, and Prevacid for treating heartburn, for more than one year have a 44 percent increased risk of breaking a hip. Dr. Colon-Emeric relates, “The widespread use of acid suppressing drugs and the associations with osteoporosis are of concern, but the research is not yet definitive on the exact causes of bone loss and whether there is a direct link.”

Will hormone treatments for prostate cancer raise risk of bone loss?
Prostate cancer is the second most common malignancy in older men and the mainstay of treatment is hormonal manipulation, either through surgery or medication, to lower testosterone levels. Low testosterone levels slow prostate cancer growth, but they also lead to loss of bone density in men. Traditionally, androgen deprivation therapies are used mainly to treat prostate cancer that has spread to other parts of the body. Because older men are being diagnosed in the early stages of prostate cancer, more of them are opting to be treated with hormone deprivation therapy earlier in the course of the disease, and this increases the risk of secondary osteoporosis.

The bisphosphonate Fosamax is usually prescribed to treat secondary osteoporosis caused by androgen deprivation, despite the limited research that has been done on its efficacy in men with prostate cancer. Clinical researchers are studying the use of new bisphosphonates, such as zoledronate and zomeda, to reduce the rate of bone loss and prevent bone fractures in patients with prostate cancer.

What balancing acts are needed for older adults?
As the links between medications and secondary osteoporosis accumulate, primary care physicians are being increasingly called upon to screen and diagnose patients who were once thought to be at lower risk of osteoporosis. The research findings do not mean that older adults should stop taking their medications or discontinue cancer treatments, but rather that they should be made aware that osteoporosis is a possible side-effect and educated to take general steps to prevent bone loss. These steps include engaging in weight-bearing exercise, eating a diet rich in calcium and vitamin D, and avoiding smoking and alcohol. Another possibility is that more older men will have their bone density tested when they begin taking an SSRI, proton pump inhibitor, or hormone treatment, and again after they have been on the drug for a period of time, to see if their bones are thinning.