ARTICLE IN BRIEF
A new survey found that only half of MS patients are being screened and treated for osteopenia and osteoporosis. MS experts highlight the need to focus on promoting bone health among these patients.
Although people with multiple sclerosis (MS) are at increased risk for developing osteopenia and osteoporosis, preventive measures to help preserve their bone health are prescribed only infrequently, according to a paper appearing in the Nov. 3 edition of Neurology.
The investigators, led by Ruth Anne Marrie, MD, PhD, of the Department of Medicine at the University of Manitoba in Winnipeg Canada, surveyed 9,000 participants of the North American Research Committee on Multiple Sclerosis (NARCOMS) Registry, to assess the frequency of osteoporosis, fractures, and clinical risk factors for fracture in MS.
Approximately 27 percent of the NARCOMS respondents reported having low bone mass — either osteoporosis or osteopenia. The odds of osteoporosis were higher in women than in men, and increased steadily with increasing age and higher levels of disability. Impaired mobility was also associated with an increased risk of fractures; approximately 16 percent of survey participants had had a fracture after age 13, with nearly half of those experiencing multiple fractures.
Despite these risk factors, preventive and screening measures for bone loss were only used about half the time in patients with MS, the researchers found. Slightly more than half of survey respondents had had bone density tests, while about half (49.8 percent) were taking calcium supplements and about 66 percent were taking vitamin D supplements.
BONE HEALTH: GAP IN MS CARE
The study points out an important gap in MS care, said Patricia Coyle, MD, professor and acting chair of neurology at the State University of New York-Stony Brook, and the director of the Stony Brook MS Comprehensive Care Center. “Neurologists probably don't focus on bone health and the difficulty with fractures in their MS patients very well, and from an awareness point of view, this study is a very valuable one,” said Dr. Coyle, who was not involved with the study.
Most physicians see osteoporosis screening and prevention as the purview of the primary care provider — but for many MS patients, the neurologist is their primary care provider, Dr. Coyle pointed out. “It's our responsibility to make sure they have someone else taking care of their bone health, or assume that responsibility ourselves.”
Osteoporosis tends to set in earlier in both women and men with MS, said Bianca Weinstock-Guttman, MD, associate professor of neurology at State University of New York at Buffalo, and the director of the Baird MS Center at the Jacobs Neurological Institute. “In evaluating the bone scans of our MS patients, we've found it much more frequently at earlier ages.”
DISEASE PROCESS AFFECTS BONE LOSS
In addition to the obvious reasons why people with MS might have increased risk of bone loss, such as impaired mobility, there may be underlying factors having to do with the disease process itself that promote bone loss. “Disability and being sedentary are the easiest problems to follow and evaluate, of course, and multiple studies have identified limited mobility as a primary factor associated with increased bone loss in MS,” said Dr. Weinstock-Guttman. “But it's much more than this. I believe that the abnormalities of the inflammatory process in MS are probably culprits as well.”
For example, Dr. Weinstock-Guttman and her team reported in a 2006 paper in the journal Multiple Sclerosis that osteocalcin, a calcium-binding protein in bone that is often used as a biomarker for the bone formation process, is decreased in MS patients. But they found increased levels of osteocalcin in the blood of MS patients after one year of treatment with interferon. “So, eventually, we may be able to use interferon to both control the disease itself and the bone homeostasis as well.”
Vitamin D also may play a unique role in MS patients and bone loss. “It's interesting to speculate, with the current focus on vitamin D deficiency as a significant risk factor for development of MS, that perhaps this puts the MS patient per se at greater risk for this problem,” said Dr. Coyle. “We know that vitamin D is fundamental to bone health, and also has an impact on the immune system. Low levels of vitamin D make individuals more vulnerable to infection, and there clearly seems to be a relationship between low levels of vitamin D and MS risk.”
“We have to take care of so many things: disease stability, changes in medications, side effects,” Dr. Weinstock-Guttman said. “Bones aren't seen as equally important, but that means our patients may fall through the cracks in this regard.”
The AAN Multiple Sclerosis Section is developing a task force on best practices for MS clinics, which Dr. Weinstock-Guttman is chairing. “We are trying to identify the most important elements to be considered, and will be reporting our first findings at the AAN annual meeting in Toronto,” she said. “Two of the most important elements brought up so far have indeed been monitoring vitamin D levels and implementing regular bone scans.”
“With the shift in health care emphasis, we're focusing more and more on prevention, and this becomes more important,” said Dr. Coyle. “It would be very nice if this research would ultimately lead to some sort of consensus statement on exactly what sort of preventive measures should be evaluated, and a heightened awareness of what a preventive osteoporosis program involves, which is not now widespread in the neurologic community.”
• Marrie RA, Cutter G, Vollmer T, et al. A cross-sectional study of bone health in multiple sclerosis. Neurology
• Abraham AK, Ramanathan M, Mager DE, et al. Mechanisms of interferon-beta effects on bone homeostasis. Biochem Pharmacol
• Weinstock-Guttman B, Ramanathan M, et al. Interferon-beta modulates bone-associated cytokines and osteoclast precursor activity in multiple sclerosis patients. Mult Scler
• Munger KL, Levin LI, Ascherio A. Serum 25-hydroxyvitamin D levels and risk of multiple sclerosis. JAMA
• Munger, KL, Zhang SM, O'Reilly E, et al. Vitamin D intake and incidence of multiple sclerosis. Neurology