Diagnosing and Treating Osteoporosis Among Adults With Disabilities

Jon J. Michnovicz, MD, PhD
Assistant Medical Director
United Cerebral Palsy of New York City, Inc.

The economic burden of osteoporosis in America is huge. Over $38 million is spent each day in this country ($14 billion annually) in the direct medical costs of treating fractures resulting from osteoporosis.

For adults with physical disabilities, such as cerebral palsy, spina bifida, multiple sclerosis and muscular dystrophy, the problem of osteoporosis is greatly magnified. We must focus much more energy on disease prevention, because osteoporosis is a preventable illness that can complicate the many challenges faced by people living with serious physical disabilities.

What Is Osteoporosis?
Osteoporosis simply means less calcium in one's bones compared with the average amount usually found in people of a certain age or gender. While the term osteoporosis may conjure up the image of an elderly lady stooped over her cane, thin bones can occur in men and women, as well as young adults. Adults with disabilities nearly always have less bone calcium as a result of several factors, including muscle disuse, diet, and medications.

Calcium is the mineral that makes our bones rigid and strong. As bone calcium is lost through osteoporosis, the bones become more thin and fragile. This is instantly recognizable under a microscope. When compared with healthy bones, the osteoporotic bone looks like trouble just waiting to happen.

To understand why osteoporosis is more problematic among people with physical disabilities, we need to understand that living bone contains two cell types: the "osteoblasts" which build bone, and the "osteoclasts" which dissolve bone. These cells are at work around the clock, balancing one another to keep bones healthy. In osteoporosis, unfortunately, the bone-dissolving cells get the upper hand.

Take, for example, a person who suddenly becomes paralyzed due to a spinal cord injury. The unused muscles soon weaken and atrophy, and the bones are no longer in motion. Normally, bone-building cells depend upon active muscle use to do their job, which is why the bones of the right arm are a bit heavier than those of the left arm in a right-handed person. With paralysis, the bone-dissolving and bone-building cells are no longer balanced, and bone loss sets in. Over time, those bones are much more susceptible to fracture. Every time muscles are used, bone is built. People with physical disabilities often cannot protect themselves in this way.

Risk Factors for Osteoporosis
In addition to weak or unused muscles, there are other major risk factors for osteoporosis among adults with disabilities. Adequate dietary calcium is a big contributor to strong bones. Research studies have shown that many young adults in the US simply do not consume the recommended amounts of calcium on a daily basis. Young adults with disabilities may have an even greater problem with dietary calcium as a result of swallowing problems, digestive disorders, and concurrent use of medications such as Phenobarbital and Dilantin (for seizures) that interfere with the body's ability to absorb calcium.

Other drugs that may interfere with calcium absorption in healthy bones include steroids (for asthma), thyroid hormones, and certain psychiatric medications (such as Haldol). Young women with disabilities who become either obese or excessively thin may have menstrual irregularities, which also will threaten the bones. There are some dietary strategies, however, that can ensure sufficient calcium intake.

The greatest risk factor for adults with disabilities, however, is lack of exercise, such as weight training, swimming, cycling, etc. These exercises require the use of certain equipment or programs. In most cases, a person with a significant physical disability encounters difficulty because the exercise facilities lack accessibility.

Prevention and Treatment of Osteoporosis

Bone Density Testing
A first step in fighting osteoporosis is to monitor a person's bone for evidence of calcium loss. This can be accomplished by a DEXA-type scan, which uses a device that measures the density of bone in key areas of the body, such as the spine and hip. The bone density is then compared to other people of that age and sex.

This type of machine can present some problems for individuals with severe disabilities who have scoliosis or muscle contractures since the machine requires that the individual lie flat and motionless on his or her back for a period of time. One useful strategy for people with severe disabilities is to monitor the bone only at those sites where a good reading can be taken. However, this approach requires a great deal of patience and accuracy on the part of the bone density lab technician, as well as the challenge of remaining motionless for the individual being tested. Newer technologies are being introduced to measure the bone density in the heel. Another device uses sound waves to measure the fracture potential of bones in the arms and legs.

Another reason to perform routine bone density testing is to monitor changes over time. Since the risk of osteoporosis is so high in people with disabilities, it is important to see whether the condition has worsened, and to determine whether a specific treatment (discussed below) is having any beneficial effect.

Dietary Calcium
Adequate calcium intake has been shown to protect the skeleton, to lower blood pressure, to reduce the risk of colon cancer, and even to reduce the formation of kidney stones. The optimum amount of dietary calcium varies somewhat throughout life, but it falls between 1000-1300 mg per day (see Table 1).

How does one go about getting this much calcium? Many foods are a good source. A single serving of dairy products delivers around 250 mg of calcium. This includes an 8 oz. glass of milk, two slices of yellow cheese, or a cup of yogurt. Other dietary sources of calcium, such as sardines (2 oz, 220 mg), an orange (50 mg), collard greens (1/2 cup cooked, 180 mg), or beans (1/2 cup cooked, 90 mg). Several cereals are now fortified with calcium, and orange juice can also be purchased with added calcium equal to a serving of milk.

In addition, calcium supplements are an excellent way to get added calcium. The average pill will usually state that it contains 500 mg of calcium, but only about 200 mg of this is actually usable calcium. Always read the label, and be sure to purchase a good quality, name-brand product.

Vitamin D helps to capture the calcium in our diets and make it available to the bones. The daily recommended amount of vitamin D is 400 units, which can be obtained through a combination of dairy products, a daily multi-vitamin, and a small amount of sunlight exposure each day.

Table 1

Source: Heaney, R.P. There should be a dietary guideline for calcium. American Journal of Clinical Nutrition, vol. 71, pp. 657-661, 2000.

Exercise
Resistance exercise on a regular basis is important for everyone, especially people with a physical disability. Exercise does not need to be strenuous to be beneficial. A good start is to aim for regular exercise three times a week for about 30-45 minutes each time (see below for components).

Components of an Exercise Session for Individuals with Disabilities

1) Warm-up period of 5-10 minutes that includes 2-5 minutes of gentle activity focusing on the muscles and joints, such as slow walking or slow wheeling, and 2-5 minutes of stretching.

2) Specific exercise activity for 20-30 minutes, such as aerobic exercise, resistance exercise (weight training), swimming, aquatics, cycling, etc.

3) Cool-down period of 5 minutes or longer.

Exercise should be engaged in regularly, at least 3-5 times per week. In addition, a physician or other health care provider should be consulted before initiating an exercise program for a child, teen or adult with disabilities, particularly if the individual is taking medication and/or has a chronic health problem.

Source: "Exercise Principles and Guidelines for Persons with Cerebral Palsy and Neuromuscular Disorders," published by the United Cerebral Palsy Research and Educational Foundation. Copies are available through UCP, 1660 L Street NW, Suite 700, Washington, DC 20036. Telephone 800-USA-5UCP.

Proper Lifting and Transferring
Probably the single greatest risk for fracture in an adult with severe physical disabilities occurs every time he or she moves from one location to another, whether it is from bed to wheelchair, or wheelchair to shower, etc. When lifting and/or transferring, everyone associated with the individual being transferred must move slowly and carefully. It is helpful to break down all movements into small steps. Watch for seatbelts, foot straps, or other obstacles that might lead to an accident. Never lift someone from underneath the arms. It is best to have the individual being moved do as much of the work as possible. It is helpful to consult with a licensed physical therapist if advice is needed on proper techniques for lifting or moving a person with disabilities.

Also, never squeeze the person while lifting. Lock your arms around the person's chest by grasping your forearms together, being careful not to squeeze the rib cage. Individuals who are able to take some steps should rely on proper positioning and bear weight on the palms of their hands when rising from a seated position.

Medications
Several medications have been developed in recent years to treat osteoporosis. The first, Fosamax, is now widely used. This drug directly impedes the action of bone-dissolving cells in bone, and therefore, may find widespread application among adults with disabilities. Recently, the FDA approved the use of once weekly dosage (70 mg) to help limit the gastrointestinal side effects. The second drug, Evista, is a hormone-like agent recently developed for older women. This drug acts somewhat like estrogen replacement therapy in helping to build bones, but without the side effects of estrogen therapy. A third widely used drug is Calcitonin, a naturally occurring hormone that helps to build new bone. This medication cannot be taken orally and is most often administered in the form of a nasal spray. Estrogen replacement therapy (called ERT or HRT) is another treatment that has been used by millions of women for many years to prevent bone loss.

Improving with Age
Osteoporosis is among the many medical issues that accompany aging. As with heart disease, future research will continue to yield insights to its prevention and treatment. Physicians in the field of rehabilitative medicine need to take a more active role in applying these insights to the care of men and women with severe physical disabilities. Our goal must be "healthy aging." We are all growing older, and we need to protect the independence for which so many have fought so hard. With good medical care and a healthy dose of prevention, individuals with physical challenges will continue to enjoy longer, healthier, and more independent lives.