By Deborah T. Gold, Kristine D. Harper and Kathy Shipp

Osteoporosis is a silent disease that affects both women and men, but women most especially. By the time a woman has reached age 60, she may have already had enough bone loss to suffer her first vertebral fracture, and, irrespective of changes in bone density, one fracture increases the risk of another. A woman who has suffered her first vertebral fracture at 60 may be looking at her retirement years as an osteoporotic woman.

By far the worst clinical complication of osteoporosis is hip fracture. Between 6percent and 20 percent of patients who fracture their hips will die within the first year of the fracture, and most of these within the first four months. Among those who survive, fewer than 30 percent of men and women who fracture a hip will return to the same level of functioning one year after the fracture, and many will spend a significant amount of time, perhaps the remainder of their lives, in institutional care.

Currently, 20 million American women and 5million men have osteoporosis, which is defined as significantly less-than-normal bone mass (with normal bone mass taken as the average bone mass of a 30-year-old woman). However, if low bone mass did not lead to fractures, osteoporosis would not be a problem. We estimate that the direct medical cost of osteoporotic fractures is approximately $15 billion a year. Today, in the United States, there are 250,000 cases of hip fracture every year, and we anticipate that halfway through the next century that number will at least double.

Bone is living tissue that rejuvenates and repairs itself throughout a person's life. In addition to providing the body's skeleton, bones also store 99.9 percent of the body's calcium, a substance necessary to contract the heart muscles, conduct nerve impulses and keep cells healthy. The bones' ability to rejuvenate and to supply calcium to the heart, liver and nerves is called bone "remodeling." In the most simple terms, a bone cell called an osteoclast digests or "resorbs" bone tissue, and a second cell, an osteoblast, repairs the space left by the osteoclast by manufacturing collagen tissue and filling the hole with new, rejuvenated bone. From birth until approximately late teens or early 20s, the body produces more bone than it destroys, making deposits in a "bone bank." But shortly after the body reaches peak bone mass, it begins to withdraw deposits from the bone bank; the rate of loss is small, but nonetheless it amounts to about a half a percent a year.

At menopause, for both men and women (women lose estrogen and men lose testosterone), there is an unabated increase in the activity of the osteoclast that digests bone, and the osteoblast does not quite keep pace with filling in the holes. It is estimated that an average woman in the United States loses about 2­3 percent of bone mass per year for the first five years after menopause; a woman who is a rapid loser can lose as much as 4­6 percent per year. We also know that there are men and women who continue to lose bone quite rapidly well into their 70s and 80s.

There are several causes of osteoporosis that can be affected by changes in lifestyle or by avoiding certain medications. Steroids, in particular, cause bone loss. So does inactivity, smoking, alcoholism and low calcium intake.

Preventing Bone Loss

There are a number of approved drugs that reduce bone lose effectively by stopping the action of the osteoclast. The drugs in this class are estrogens, calcitonin and alendrenate sodium. Calcium, too, blocks the osteoclast. Wherever we look on the globe, the higher the calcium intake in the diet, the greater the bone density of the population. We should all be getting between 1,200 and 1,500 mg of calcium per day, but the usual diet for Americans includes only 400­700 mg per day. So calcium supplements are definitely in order for anyone who does not regularly drink several glasses of milk or have two servings of cheese daily.

We have known for at least 30 years that most of the time decreases in estrogen are the culprits in female osteoporosis. It is estimated that if women were to use hormone replacement therapy (hrt) at menopause for five to ten years, we could probably reduce the risk of hip fractures by 50 percent and vertebral fractures by 70 percent. However, we also know that most postmenopausal women do not use hrt because of their fears that it may cause cancer. For every 100 prescriptions written for hrt in this country, 50 percent are never filled, and only 20 percent of those who begin hrt are still using it a year later. Only by using hrt for the entire postmenopausal life course can a woman be sure to reduce the risk of osteoporosis.

Could we develop the perfect estrogen? The perfect estrogen would prevent bone loss and decrease the risk of fracture, it would protect against heart disease, and it would not cause cancer of the uterus or the breast. There is a class of drugs being developed, called selective estrogen receptor modulators (serms), that may actually have all of these effects.

But even now, for those women who will not or cannot take hormone replacement but are rapidly losing bone mass, there is an alternative drug therapy: alendrenate sodium. Clinical trial data have shown that alendrenate sodium has positive effects on bone density in all regions of the body. We know from the core clinical trials that it also reduces hip fractures and vertebral fractures by 50 percent. For those who are sensitive to the side effects of alendrenate sodium (including esophageal problems), there is a another drug, calcitonin, that is an approved therapy for osteoporosis. However, data do not support the claims that calcitonin reduces fractures.

The Social Consequences of Osteoporosis

Osteoporosis has a negative impact on quality of life when the accumulated deficits of the disease lead to anxiety, depression and reduced function. A person who has a single wrist fracture or a single vertebral fracture usually has no long-term effects. Those fractures will heal without major consequences. But when someone has multiple fractures or when a hip fracture occurs, life starts to deteriorate.

When a person first hears the diagnosis of osteoporosis, she or he may decide to do anything so as never to have another fracture. This includes not going out or exercising because of fear that a bone will break. The person may stop having social interactions or going to crowded places like malls because of the fear of being bumped. When, however, the second fracture does occur (and it is very likely that it will), that anxiety can turn into depression.

In treating osteoporosis, most physicians deal with the bones without thinking about how people feel about the disease. But with the number of effective antidepressant medications now available to us, we can do something about the depression as well. There are interesting data from the National Institute of Mental Health comparing women who have had or are having a major depressive episode with a group of similar women without such experience. When the bone density of the women in both groups was compared, the bone density of the depressed women was significantly lower than that of the nondepressed women. We do not know from this study whether the depression causes the osteoporosis (because the women stopped being physically active) or whether the physiological changes that occur with osteoporosis lead to increased risk for depression. But we do know there is a correlation that needs further study.

People with osteoporosis also have to deal with chronic pain. Acute pain resulting from a fracture can be managed effectively with exercise and analgesic drugs for the first month following the fracture. But analgesics do not help the chronic pain caused by multiple fractures and changes in posture due to osteoporosis. These drugs can make people dizzy and sleepy, which in turn will increase the risk of falls and fractures. Biofeedback and visualization techniques work extremely well for some people, but the key to managing chronic osteoporotic pain lies with the physical therapist. The physical therapist makes a more important contribution to the daily quality of a patient's life than do any of the other healthcare professionals involved in treating osteoporosis.

Exercise, Exercise, Exercise

Normally there is enough stress on the bones in the course of daily activity to maintain bone mass most of the time. But mass can actually be increased by weight-bearing and resistive exercise.

Resistive exercise is strength training, the sort of exercise one gets by using the equipment found in health clubs. This activity increases bone density by 1­5 percent if a person continues the activity very regularly two to three times a week, 20­30 minutes per session, over a period of one to three years. Weight-bearing exercise, in which the body holds itself up against gravity, will increase bone density if done three to four times a week, 30­45 minutes per session. Exercise must be done regularly, however, because bone loss will occur as soon the exercise regimen stops. There are many forms of weight-bearing exercise, including walking, jogging, and line dancing. Doing push-ups, too, is weight-bearing exercise and very important because it develops the bone in the upper extremities. Even the frailest patients can do this exercise by pushing out from a wall.

Posture is another important factor in preventing fractures, specifically the vertebral fractures that often cause kyphotic deformity, usually known as dowager's hump. Sitting erect and lifting correctly are crucial. Both bending forward and twisting the upper body are bad for the spine. In addition, a form of exercise developed for osteoporotic people called extension exercises, bending in a backward direction, have been shown to dramatically reduce the incidence of new vertebral fractures. Our clinical experience also indicates that these exercises can reduce pain substantially. These exercises are especially important for people with osteoporosis and the beginnings of kyphotic deformity, but they can also be done to prevent it.

Preventing Osteoporosis--A Lifespan Approach

Calcium intake at all ages is crucial. Children under 10 need 800­1,200 mg per day. People between the ages of 11 and 24 need 1,200­1,500 mg per day. Men and women between 25 and 64 require 1,000 mg. Beyond the age of 65, men and women require 1,500 mg. But postmenopausal women using hormone replacement therapy do not need more than 1,000 mg of calcium a day.

To minimize the chances of developing osteoporosis, parents should encourage children to be physically active, engage in sports and participate in physical recreational activities. Parents can also help by encouraging good posture and teaching positive habits about bending and lifting from an early age. Adolescents should be encouraged to continue to have a physically active lifestyle, but excessive exercise and reduction of weight and body fat must be avoided (anorexia nervosa and bulimia in adolescence can cause osteoporosis in later life). Adults at any age should begin an exercise regimen that includes resistance training and weight-bearing exercise, and this should be continued throughout the life course. Older people without osteoporosis should continue or begin exercise regimens. They should also modify their living environments to minimize the risk of falling (see sidebar). Even people with established osteoporosis will benefit from weight-bearing, resistive and extension exercises.

1. Remove throw rugs and make certain that carpet edges are securely fastened to the floor.
   
   
2. Reduce clutter, especially in high-traffic areas.
   
   
3. Install or maintain sturdy handrails at stairs.
   
   
4. Increase wattage of lighting in hallways, bathrooms, kitchens, stairwells and entrances to homes.
   
   
5. Use night lights near the bed, in hallways and in bathrooms to improve night safety.
   
   
6. Install safety handrails in shower, tub and around the toilet. Bathtub and shower stall should have nonskid surfaces.
   
   
7. When you must reach for something high, use a safety step stool--one with wide steps and a friction surface to stand on. A step stool equipped with a high handrail is preferred.
   
   
8. If a cane or walker has been recommended, use it.
   
   
9. Wear supportive, cushioned, low-heeled shoes. Avoid scuffs (backless bedroom slippers) and high heels.
   
   
10. Avoid rushing to answer the phone or doorbell. A portable phone is a good idea for security and safety.
    
    
11. Have sand or salt available to spread on porches, stairs and sidewalks during snowy, icy weather.

Source: Working with Patients to Prevent, Treat and Manage Osteoporosis: A Curriculum Guide for the Health Professions, published in 1996 by the National Fund for Medical Education.

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