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Our bones are like ongoing construction projects. Throughout life, we are constantly forming new bone and dissolving old bone, a process called bone remodeling or bone turnover. Remodeling helps our bones stay healthy. However, as we age, this remodeling cycle becomes unbalanced. More bone is dissolved than is formed, with the result being an overall bone loss. This process becomes especially active in women after menopause, who can lose up to 7% of their bone each year. Men also lose bone with age, although the rate of loss is less than in women. Osteoporosis develops when so much bone has been lost that the integrity of the bone is weakened and the risk of fractures is especially increased. Fractures of the spine, hip, and wrist are most common. Each year in the United States, more than 250,000 women break a hip, and more than 500,000 break a spinal vertebra (the bones that make up the spine). Add to this the fractures in men, and approximately one million older Americans suffer fractures related to osteoporosis every year. In addition to fractures, osteoporosis causes pain, curvature of the spine, loss in height, and other changes in posture and body shape. Overall, osteoporosis can lead to decreased quality of life, decreased independence, increased illness, and early death. People with fractures of the spine from osteoporosis may be unable to bathe, dress, or walk independently. Approximately one in five older persons dies within one year of a hip fracture, and approximately half of women with hip fractures do not fully recover previous function.
Approximately three quarters of osteoporosis is inherited from our parents and grandparents through our genes. However, there are also other risk factors. Although we all lose bone as we age, the rate of loss becomes especially great in women after menopause. This is caused by a decrease in estrogen levels. Abnormally low levels of sex hormones (eg, estrogen or testosterone) can also cause osteoporosis in men. Deficiencies in calcium and vitamin D are strong risk factors. Calcium is the main building block of bone, and vitamin D helps control calcium absorption and distribution in the body. Many people tend to eat fewer foods that are high in calcium as they get older (especially dairy products), compared with when they were younger. Also, many older people spend less time in the sun, meaning less skin exposure to sunlight, which is a source of vitamin D. Digestive tract disturbances can also decrease calcium absorption. Osteoporosis can also be associated with certain medications, especially corticosteroids. Discuss all medications that you are taking with your health care provider and always check with him or her before changing or stopping any medications. As part of an assessment for osteoporosis, your healthcare provider will ask about the various risk factors that you might have. However, the main tool used to detect osteoporosis is measurement of the amount of bone in your body, which is often referred to as "bone mass density" (BDM). Your BMD is also the best predictor of a fracture. In general, the risk for a fracture goes up as the BMD score goes down. For example, a fracture is 10 times more likely in women who have the lowest BMD levels compared with women who have high bone density. Bone density is often measured at the hip, spine, wrist, or heel using a variety of techniques. The most common methods use low levels of X-rays to measure bone density. The National Osteoporosis Foundation, in conjunction with numerous national health organizations, recommends BMD testing for all women aged 65 years and older, regardless of their risk factors. Testing is also recommended for some men or younger women who have certain risk factors.
Your healthcare provider will also want to check for osteoporosis after any fracture that has been caused by minimal trauma. Many fractures of the spinal vertebrae do not result in any symptoms, and may be noticed only because of decreased height, increased curvature to the spine, or simply because clothes no longer fit properly. Spinal fractures may also cause back pain, which can last 2-4 weeks and be quite debilitating. The main treatment for osteoporosis is prevention. The goal is to minimize bone loss as we age and to reduce the risk of fractures. The keys to prevention are dealing with risk factors and prudent testing of BMD. The most important risk factors that we can change are exercise and diet. Exercise is an important part of osteoporosis treatment and prevention. Frequent (eg, three times per week), moderate to vigorous exercise is associated with increased bone mass and decreased fractures. (In contrast, excessive exercise in young women can lead to bone loss because they often have a decrease in their estrogen.) Weight-bearing exercises such as walking are best (see also Physical Activity). Strength training (eg, weight lifting and other forms of resistance training) strengthens hip bones and improves muscle mass, strength, and balance in women after menopause. This reduces both falls and fractures.Likewise, a marked decrease in physical activity (eg, long-term bed rest) results in a loss of bone mass. This is one reason why it is important to return to activity as soon as possible after a stroke, surgery, or other debilitating event (see also Rehabilitation ).Calcium and vitamin D are required for bone health at all ages. To maintain good calcium balance, all adults 65 years and older and younger women after menopause should have a calcium intake of at least 1200 mg per day. This can be in the form of foods high in calcium , such as dairy products, eggs, and broccoli, or as calcium supplements, fortified fruit juices, etc. The average dietary intake of calcium for postmenopausal women in the United States averages 500-700 mg per day. Therefore, most American women need calcium supplementation to ensure adequate intake.Calcium Content of Various Foods (approximate mg of calcium per serving) Dairy Products Other Foods
Older adults also require between 400 and 800 IU of vitamin D per day. Vitamin D is found in foods (eg, milk and fortified juices) and is formed in the skin through direct exposure to sunlight. However, skin changes that happen as we age result in less efficient production of vitamin D from sunlight. So, it is recommended that all adults take a daily supplement of at least 400 IU of vitamin D, which is the amount provided by most over-the-counter multivitamins. Problems with calcium or vitamin D can also be caused by diseases of the gut, liver, or kidneys. Your healthcare provider will evaluate these areas and prescribe treatments if appropriate. In addition to exercise and dietary calcium intake to prevent osteoporosis, certain medications can also be used to treat osteoporosis. These include hormone therapies, such as estrogen/progesterone or calcitonin. However, because of recent research findings (discussed below), estrogen/progesterone is no longer recomended as a fist-line approach in the prevention of osteoporosis and is usually considered in women with osteoporosis only after a discussion with their healthcare provider about whether this is the best aproach. Other drugs that are used to prevent or treat osteoporosis include drugs that are specifically designed to increase bone mass. Examples of these include alendronate, raloxifene, risedronate, and ibandronate. These medications can have a number of side effects, including stomach upset, nausea, vomiting, diarrhea, and muscle pain. They are usually used to prevent osteoporosis in women at high risk as well as in women who have osteoporosis and who are at high risk of fracture. Estrogen/progesterone replacement therapy is also used for osteoporosis prevention, but it is not recommended as a first choice. Estrogen/progesterone replacement therapy decreases the risks of both osteoporosis and fractures, but some forms of estrogen therapy have also increased the risks of breast cancer, heart disease, and deep-vein thrombosis. Estrogen therapy at lower dosages may be a possibility. Recent guidelines of the US Food and Drug Administration recommend considering other treatments first: "Estrogens and combined estrogen-progestin products should only be considered for women with significant risk of osteoporosis that outweighs the risks of the drug." Fractures that accompany osteoporosis are usually managed by standard medical or surgical treatments. Newer treatments for fractures of the spinal vertebrae involve injecting bone cement into the collapsed vertebrae (vertebroplasty) or placing a "balloon" into the fractured vertebrae (kyphoplasty). Some early research suggests that these methods may decrease pain and improve quality of life and function. Pain caused by fractures can be controlled by anti-inflammatory drugs and narcotics. Physical therapy is also an important part of osteoporosis treatment programs for the management of acute and chronic pain (see also Rehabilitation ). Physical therapists can provide postural exercises, alternative techniques for pain reduction, and information on changes in body mechanics that may help prevent future fractures. There are also support groups for people with osteoporosis.Cigarette smoking and alcohol abuse are also risk factors for osteoporosis. Quitting smoking cuts down your risk and provides many other health benefits, including decreased risk of cancer, heart attack, and lung disease. You are never too old to quit! Osteomalacia is much less common than osteoporosis. It is a specific problem of bone mineralization that leads to pain, muscle weakness, and fractures. The most common cause of osteomalacia in older adults is vitamin D deficiency due to inadequate intake. In addition, excessive use of some medications, chronic kidney failure, liver disease, and problems with gut absorption also may result in osteomalacia. Osteomalacia is often confusing, and making a diagnosis is difficult. The only way to know for sure is by a bone biopsy (ie, removing a small piece of bone and examining it under the microscope). Prevention and treatment of osteomalacia involve vitamin D supplementation. To avoid problems with osteomalacia, older adults can take vitamin D at 800 IU per day, the amount generally included in two multivitamins. However, because too much of certain vitamins can also be harmful, you should talk to your health care provider first to make sure that it is okay for you to take more than one multivitamin per day. |
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Published: 3/15/2005