THE BONE ZONE
Developing a winning strategy can help put the brakes on bone loss.
For individuals with osteoporosis, it can happen in an instant. Step off a curb, slip on a rug, sneeze, or even hug too tightly, and snap-a bone breaks. The hardest, most durable structures in the human body, bones are built tough, designed to protect organs, anchor muscles, as well as help us sit, stand, run, walk, and carry us through life.
However, over time, the architecture of bone changes. Bone, like many tissues, is constantly broken down and rebuilt. But as we age, the delicate balance of breakdown and buildup shifts, triggering a gradual but progressive loss of bone. All too often, the "silent" process occurs so slowly that neither doctor nor patient is aware of the underlying bone loss until the patient suffers from a broken bone or collapsed vertebra. Victims are often sidelined with debilitating fractures, loss of independence, and in general are out of the game. One in two women and one in four men over age 50 will suffer osteoporosis-related fractures.
Fortunately, improved treatment, nutritional interventions, regular activity and screening technology are brightening the outlook for better bone health.
How can you "beat the break?" To bring you the latest news on osteoporosls and risk prevention, the Post Interviewed leading osteoporosls specialist Michèle F. Bellantonl, M.D., associate professor of medicine. Division of Geriatric Medicine and Gerontology, Johns Hopkins University School of Medicine.
Q: Are researchers closer to understanding what causes osteoporosis?
Dr. Bellantonv Yes. We know more about the changes in reproductive hormones and how they influence bone. There Is some understanding of the role of other hormones, such as growth hormone. We also know more about the digestive issues and are trying to target beneficial therapies without the harmful side effects. One challenge we face is developing effective treatments to increase bone mass. With osteoporosls treatment, we really want to prevent fractures and build strong bone.
We don't have diagnostic technology that tells us if or when we've Improved the strength of bone. The dual-energy x-ray absorptiometry (DXA) is a surrogate measure; it's measuring density. Density does not equate directly with strength. Bone gets its strength, in part, from Its three-dimensional architecture. I use the analogy of the way bridges are built. Bridges, in general, are not solid mass, but shored up by interlocking metals. In the case of bone, proteins are interwoven in a pattern with calcium placed on them. You get greater increase in strength with minimal increase in density when you undergo osteoporosis treatment, but our present technology with DXA is not sensitive enough to detect the change.
In fact, we do the follow-up of density on a two-year Interval because things change so slowly. We're trying to halt the progression of bone loss that we anticipate with aging. Good research is in progress to improve our diagnostics, in particular microscopic MRI scanning. This technology produces images of bone at a magnification comparable to looking at the piece of bone under the microscope, only you don't have to remove the bone. That information might give us a better handle on how we're changing the architecture of bone in response to treatment.
Q: How important is physical activity in reducing the risk of fracture?
Dr. Bellantoni: Lack of physical activity is a significant problem. Sedentary people lose bone mass. People who are at bed rest for three weeks with the flu, for example, lose bone. The lack of physical activity on bones weakens them.
Improving muscle strength and coordination can help prevent falls, so that is important. You often need two things for a fracture-trauma and weak bones. With exercise, you are making an impact on the other side of the equation-fall prevention. In fact, Medicare pays for a physical therapy evaluation and treatment program with a diagnosis of osteoporosis. By becoming more physically active, individuals could reduce their risk of falls.
The best geriatric doctors I know are physically active. They find an exercise program they enjoy and can sustain. I'm a dancer. You can enjoy physical aerobics and strengthening through dance. And I have some very osteoporotic patients who are incredible gardeners. The point is: physical activity is important.
Q: Is there a natural decline in hormones that regulate bone metabolism?
Dr. Bellantoni: Yes. In women who are lean, the decline is very pronounced during the menopausal transition. Men do not experience as significant a drop in hormones; it is a more gradual progression. Men start out with a higher bone mass in their 30s, so, in fact, they can afford to lose more before they're at risk for fracture. In the past, men had a shorter life expectancy, so they died of something else before they were old enough to experience a fracture or become frail. However, we're beginning to see a change. As a geriatrician, I consult for patients who have had fracture, and I certainly see my share of older men now. Men with Parkinson's dis ease and other conditions of the nervous system experience difficulty with walking. Older adults who survive stroke may still have some physical impairment after physical rehabilitation. The side impaired by the stroke loses bone rapidly and falls are more common when muscle weakness persists after stroke.
Q: What are the current screening recommendations for osteoporosis?
Dr. Bellantoni: The U.S. Preventive Task Force specifically addresses this issue, but many primary-care providers and women aren't aware of the guidelines. The current recommendation is to begin screening for bone density at age 65 years for women. However, the recommendation is reduced to age 60 years if a woman has risk factors for osteoporosis that primarily include significant leanness and family history. For example, the most significant risk in terms of family history is when a parent had a hip fracture. Should we consider a woman aged 60 whose sister had a forearm fracture when she was a few years younger? That is reasonable. We currently do not have widely accepted recommendations for screening of men. In addition to family history and leanness, medical conditions and medical treatments can put an individual at risk for osteoporosis. In these individuals, bone assessment is appropriate as part of their overall . healthcare plan. The focus of medicine in older adults is on lifestyle and behavior. In the case of osteoporosis, it is a matter of adequate nutrition, calcium, vitamin D, physical activity, and avoiding medicines that are not medically necessary.
Q: What medical conditions can increase risk for osteoporosis?
Dr. Bellantonv Medical conditions that put individuals at risk for osteoporosis include: rheumatoid arthritis; inflammatory bowel conditions, particularly Crohn's disease; and celiac disease-an allergy to a substance in wheat that makes it difficult for the digestive system to process important nutrients, in particular calcium and vitamin D. These conditions help explain the association with osteoporosis at young ages. For healthcare providers treating individuals with these conditions, it is important to be aware of and pay attention to these conditions because there are effective preventive treatments for that group.
Q: Would you elaborate on medications that may increase risk?
Dr. Bellantonv Medications used to treat other medical conditions can have an impact on bone health. The most common are the anti-inflammatory steroid medicines used for autoimmune conditions, such as rheumatoid arthritis, lupus, and emphysema.
However, some seizure medicines-such as the older medicine phenytoin (Dilantin)-impair vitamin D metabolism. While the current trend in seizure management is not to use that class of medicine, younger adults-thirty-year-olds-treated for ten or twenty years with phenytoin are beginning to experience fractures as young adults. If an internist sees a 30-year-old with a seizure disorder, they should ask if the patient took phenytoin for a long time. If so, they should advise the individual that they are at a much higher risk of fracture than other 30-year-olds who are otherwise healthy. Even if they outgrew the seizure disorder, they may still have to cope with the drug's potential consequences on bone health.
Newer chemotherapy agents, such as Arimidex for breast cancer and prostate cancer agents, such as Lupron, also affect bone loss. Men who undergo surgical removal of the testes to treat prostate cancer rapidly lose bone. Today, men are diagnosed at much younger ages with prostate cancer and begin treatment. When these men enter their 70s, they experience bone fractures.
Another group of drugs that concern me include drugs to treat acid reflux. The FDA approved these prescription medications as shortterm treatment of ulcers in the lower stomach and small bowel or acid reflux symptoms. However, the drugs effectively treat symptoms of heartburn, so they're used frequently for long periods of time and are now readily available over the counter. The challenge is that stomach acid serves many roles, including one in the digestion of calcium. A study published last year associated long-term use of high doses of the antacids with hip fracture-the most significant fracture. This is new information. The good news is that by doing a bone density and monitoring bone health, we have effective treatments.
Q: To counteract the effects, do you supplement with calcium?
Dr. Bellantoni: In some patients, the long-term use of these acid reflux medications is deemed medically necessary. For them, I recommend calcium citrate, which is easier to digest and requires less stomach acid than calcium carbonate supplements. I also raise the total daily intake. For example, in an otherwise healthy adult with osteoporosis but without digestive concerns, I'm happy with the daily recommendation of 1,200 mg of elemental calcium. But in an individual with digestive concerns, I want 1,500 mg daily or higher because they won't adequately digest the full amount; it passes through without being absorbed by the body.
Q: Should patients raise these issues during routine office visits?
Dr. Bellantoni: I encourage adults to become aware of preventive health and understand their condition. Under our current U.S. healthcare reimbursement system, medical providers are often challenged to address preventive health issues. An individual could ask their health provider, "I'm here today because I have a fever, but we really haven't had a chance to talk about what I read in The Saturday Evening Post about children with seizure disorders experiencing a problem with bones as they get older. I took that drug; what do you think?"
Q: What is the preferred test for bone health?
Dr. Bellantoni: Dual-energy x-ray absorptlometry (DXA or DEXA) of the hip and spine is the preferred test. At age 65 years, or age 60 for people with known risk factors, we recommend a spine and a hipbone density test with DXA. They are sensitive tests, but there are challenges in Interpreting them. Many older women develop degenerative spinal changes. By degenerative changes, I'm not talking about the vertebral bodies-the actual bones, but the discs that are between the spine bones. Also, the back of each spine bone has little wings of actual joints that connect one spine bone to the next, and these can develop arthritis and degenerative changes. With degenerative changes, one of the final pathways Is calcium placed In the area of Inflammation, which can become very dense. When doing bone density testing, you cannot distinguish between the spine bone and these wings, so any calcium in the wings will show up as density. For example, a woman might have significant thinning of the bone, but the scan shows a normal result because of the calcium buildup. We don't have that issue when looking at the hip, in those who have arthritis in their hip where the long bone-the femur-connects to the pelvis.
In terms of progression of thinning of the bone with aging, unfortunately those spine bones often are affected before the hip. A 65-year-old woman may well have osteoporosis in her spine, but if she also has degenerative changes behind the spine, that reading might be higher-what I call a "false normal" reading. How do we get around that? The forearm Is another site that we can measure, and there are no technical Issues there, so I will often encourage an additional bone site to be measured, such as the forearm.
Q: Do previous fractures help predict future Incidents?
Dr. Bellantoni: Absolutely. Anytime an adult experiences a fracture. It Is important for that adult and healthcare provider to understand that some component of fragile bone may be associated with this trauma. Many hipfracture patients have had a much less significant fracture five or ten years earlier. The fracture was placed in a cast. However, no one thought. There's a problem with the strength of this bone,
For example, ice storms hit Baltimore recently, and a few women in their late fifties fell and broke their wrists. Those women now should have a bone-density scan, because they are now at higher risk for subsequent, more serious fractures than the average woman. An average woman with normal bone for her age shouldn't have fractured her arm; she would have bruised. But if a 58-year-old breaks her arm, she needs a bone-density test. Do not wait until you're age 60 or 65. That also applies to men.
If the DXA result Is positive, the provider should ask more questions to figure out why. For example, I saw a 45-year-old man who had bronchitis, coughed, and broke his rib. His internist said, "You shouldn't have done that." When I saw him, he had no risk factors, but his bone density was very low. I inquired about family history. He talked to his mom, and there was indeed a side of the family with an obvious genetic problem called osteogenesis imperfecta. This fellow and his son inherited the problem. We're managing the condition, but we didn't know about the problem until he coughed and broke his rib. The good news is, it didn't result in multiple fractures.
Q: Do you test for vitamin D deficiency?
Dr. Bellantoni: Yes. Most laboratories now offer a 25-OH vitamin D test-25-hydroxyvltamin D-to determine if bone weakness, bone malformation, or abnormal metabolism of calcium is occurring as a result of a deficiency of vitamin D. Vitamin D is a hormone that facilitates calcium absorption through the digestive system. Our bodies make vitamin D through sun exposure. The energy of the sun facilitates a chemical reaction in the skin that makes a molecule that is further refined in the liver and kidney and ultimately becomes the active form of vitamin D.
Today, we advise adults and children to stay out of the sun and use sun block to prevent skin cancer. And we're now seeing vitamin D deficiency. Vitamin D deficiency is not only harmful to bone, but also to muscle. If deficient in vitamin D, people may experience muscle or bone pain, or have a slower physical recovery from acute illnesses such as pneumonia. Blood tests at times reveal significantly below normal levels of vitamin D, so we give patients vitamin D to help get them back on their feet.
I am delighted that multiple vitamins are changing-the RDA in this country is 400 units of vitamin D; in Canada, it is 800. However, the One A Day brand vitamins for women in the past year increased vitamin D content to 800 units, and Centrum Silver contains 500 units. I would like to see more vitamins Increase vitamin D content.