More than 20 million Americans have osteoporosis and over 16 million don't even know it. This condition, in which the bones are thin, brittle and susceptible to fracture, is usually silent until a bone is broken and the individual is left with pain, deformity and possible disability. As our population ages, the numbers of those affected will soar -- unless we do something about it before it is too late! With recent advances in medical science, there is better understanding of principles in prevention and hope for improvement once damage has been done.Bone is an active tissue which remodels and rebuilds continuously. Bone grows in length and height until late adolescence, then rapidly becomes thicker and stronger over the next two years, gradually strengthens a little more until the late 20s, and then begins to thin and weaken during the remainder of one's life. During menopause, or whenever women or men lose their sex hormones, there is a rapid loss of bone over a period of several years and a worsening of age-related bone loss afterwards. As one gets older, the bone becomes less responsive to medical intervention and currently little can be done to make it more active. Consequently, the earlier we do things to help our bones, long before they become broken, the better we will be in avoiding future disability.
The interior of bone is a crass-cross lattice of miniature bridges that provide enormous stability and elasticity. Once these bridges are disrupted, however, they cannot be re-connected. When enough bridges are broken, the bone becomes structurally unsound, increasingly fragile and the risk of fracture increases exponentially. Once the first fracture occurs, one is several times more likely to have another fracture compared to an individual without broken bones.
We now know that the most critical time in one's life to establish good bone health is in the mid-teens, when the bone is strengthening and building. If this opportunity to build one's peak bone potential is lost, due to either medical illness or improper lifestyle, one may have proportionately thinner bone at each stage of their life thereafter. The loss of bone potential therefore has serious consequences during the later adult years.
There are a number of factors known to increase the risk of developing osteoporosis. These include improper nutrition, lack of exercise, genetic factors, certain medications and perhaps habits such as excessive smoking. Certain medical conditions also cause bone loss. These include deficiencies in sex hormones, excesses in hormones such as thyroid, parathyroid or cortisol, abnormalities in kidney or liver function and several types of malignant cancers. Physicians take these and many other factors into consideration when considering whether tests need to be performed to assess whether an individual has osteoporosis and then determine its cause.
Evaluation
A medical evaluation for osteoporosis includes an examination of the height, weight, whether there is pain or deformity in the bones and any evidence of underlying medical illness. In early osteoporosis, the physical examination is usually normal. When the spine becomes weak, it tends to collapse forward in small segments resulting in the forward bending known as "Dowager's Hump." In addition to problems encountered with appearance and in buying clothing, the bending also increases back pain, causes constipation and decreases the total lung volume, leaving the individual short of breath and susceptible to lung infections. Deformities in the feet may predispose to infection and pain.Laboratory evaluation may include a standard chemistry profile, complete blood count including red and white blood levels, a thyroid test and a vitamin D level. The cornerstone of the evaluation for osteoporosis, however, is a direct measurement of the bone density. One has to lose over 50% of their bone before it can be detected on a plain X-ray, so a special machine must be used to measure the bone.
The bone density evaluation involves measuring the lower spine and/or the hip(s) on a special X-ray table. The test takes approximately 5 minutes, involves minimal exposure to radiation, is relatively inexpensive and is usually covered by responsible insurance carriers. The results are accurate, meaningful and reproducible. The information gathered will be invaluable to the physician in making the initial assessment and in following the treatment results, if applicable.
Treatment
We can all make healthy choices in our lifestyle in order to ensure better bone health. Nutrition is the cornerstone of osteoporosis prevention. The most crucial nutrient for bone is calcium, but adequate calcium intake should not keep one from maintaining a good, balanced diet. This means adequate protein, low fat content and an appropriate number of calories. In people with anorexia nervosa, where individuals lose large amounts of weight, the bone density actually plummets to extremely low levels, and may never recover. The average American adult gets only 2/3 to 3/4 of the daily 1000 milligrams of calcium recommended by the consensus panel of the National Institutes of Health. Therefore, we must either increase our intake of low-fat, low-calorie dairy products or consider calcium supplements. We must keep in mind, however, that if we ignore the admonition to limit our fat intake, we will increase our risk of premature heart disease and never get the opportunity to enjoy the good bone health that we were planning for our later years.Calcium supplements vary in size, shape, content and availability to the body. Calcium carbonate, which contains 40% elemental calcium is the most popular form, but it requires the presence of acid in order to be absorbed and used by the body. It has little effect for people on antacids or many other medicines used for gastritis or ulcer disease and has limited effect in older individuals who have age-related decreases in stomach acid. Since calcium carbonate is best absorbed when taken with meals, when there is a greater concentration of acid, its absorption may be impaired by minerals and protein also contained in the meal. Calcium carbonate is also notorious for creating gas, bloating and constipation. All other calcium preparations contain a much lower percentage yield of elemental calcium, so more tablets must be consumed. The highest yield of calcium absorption is seen with calcium citrate, which has minimal gastrointestinal side-effects and may be taken on a empty stomach.
In the setting of good nutrition, weight-bearing exercise will help to strengthen bone and the improved muscle tone will help to prevent injury. In order to establish a sensible exercise program, one should use good judgment, appropriate attire, do warm-ups and cool-downs, be consistent and pay attention.
Hormone replacement therapy is the primary treatment option for postmenopausal women or for men with low hormone levels. Estrogen therapy in women, in addition to improving the bones, also reduces the risk of heart disease, urinary tract infections, cancer of the ovaries and perhaps stroke. Obviously, there are several medical conditions, such as breast carcinoma, where decreasing hormone levels is important in the therapy and hormone replacement is not advised. There is no clear evidence whether estrogen therapy increases the risk of developing breast carcinoma, but women should be vigilant in breast self-examination and keep up-to-date with screening mammography. At the present time, only a very small minority of women who should be on estrogen therapy actually take the medicine for an extended period of time. This may be due to fear of the potential risk of cancer, the hassles of having menstrual bleeding, expense of the medicine or even the lack of information regarding its potential benefits.
For people who do not, cannot or will not take hormone replacement therapy, there are two different options now available to improve the bones. Alendronate was approved by the Food and Drug Administration and became available as a prescription drug in the Fall of 1995. It is available as a pill, it must be taken on an empty stomach, it has few side-effects and is remarkably effective in improving bone density, even in elderly women without hormone therapy. We do not yet know whether this effect is additive together with the hormones, but ongoing studies will be helpful in answering this question. This is the first new drug which has been approved for osteoporosis in over several decades.
Another drug for osteoporosis is calcitonin, available by either injection or now by nasal spray. It helps to maintain bone density, but has not been shown to increase bone mass over time. It is often extremely effective in relieving pain, but carries a relatively high incidence of gastrointestinal side-effects. It has traditionally been given as a daily injection but in November, 1995 it became available as a nasal spray, which is very easy to use. One drawback of the nasal spray, however, is that it only comes as one strength so the dose cannot be adjusted.
Summary
Osteoporosis is a condition which affects millions of Americans and is likely to become more prevalent as our population ages. Prevention of osteoporosis during the teen and early adult years is far superior to any of the treatment options for older individuals. With identification of risk factors, careful examination and a few simple diagnostic tests, osteoporosis can be identified and an appropriate treatment strategy can be determined.The foundation of any reasonable approach to the treatment of osteoporosis is a sensible diet coupled with regular exercise. Early hormone replacement therapy is important to prevent the rapid loss of bone which occurs soon after the menopause. Newer medications are available to help prevent bone loss, relieve pain and even build stronger bones.
(Copyright 1995, Kim A. Carmichael, M.D.; All rights reserved)
Editor's Note:Dr. Carmichael is a medical doctor who is board certified in internal medicine, endocrinology and geriatric medicine. He has a particular interest in osteoporosis and calcium metabolism, and is on the clinical faculty of Deaconess Medical Center (St. Louis University). You may contact Dr. Carmichael at 6125 Clayton Avenue, #101, St. Louis, MO 63139 USA, Telephone: (314) 768-3220; FAX: (314) 768-5607; e-mail: 70554.306@compuserve.com
For additional information on osteoporosis, go to:
The World Summit of Osteoporosis Societies
OSTEOPOROSIS -- National Institutes of Health Consensus Development Conference Statement
Screening for Postmenopausal Osteoporosis
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