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PART III A PHYSICIAN’S PERSPECTIVE ON BONE-BUILDING
Dr. Carolyn DeMarco, M.D., a general practitioner who specializes in women’s health and alternative medicines, has kindly written Chapters 12, 13 and 14.
CHAPTER 12 PUT YOUR BONES TO THE TEST – WHO IS AT RISK FOR WEAK BONES?
A Foreword By Dr. Carolyn DeMarco There are hundreds of research studies in the medical literature that illustrate the effectiveness of diet, nutritional supplementation and core strengthening exercise programs, to halt and even reverse poor posture, misaligned biomechanical movement and osteoporosis. The groundbreaking research findings on the exciting impact of both nutrition and exercise on superior bone structure and function are quite dramatic. You can regenerate bone mineral density and bone health naturally!
As a physician, my main objective is to guide patients in maintaining optimum bone health or rebuilding bone health through a comprehensive program of nutritional supplementation and lifestyle interventions. I would like to illustrate the bone-building benefits of such an approach, of natural bone density regeneration, with this story.
Move Out Of The High Bone Fracture Risk Zone — Naturally
Sally, at 45 years of age, came to see me with a 20 percent reduction in vertebral trabecular bone mineral density expressed as a T-Score of –2. This spinal density score was low enough to put her at high risk for osteoporotic bone fracture. After 18 months on a “cell friendly” nutritious diet that emphasized alkalinizing salads, vegetables, fruit, berries, spices and herbs, a food-based bone-building supplement, weight resistant core exercise for strength and balance, and a lifestyle tune-up, she gained almost 20 percent more bone mineral density. This increase raised her vertebral density as a T-Score of almost 0, which took her out of the high bone fracture risk threshold.
While many fractures such as a wrist, finger or forearm fracture, are painful and inconvenient, others may be outright life threatening. A hip fracture, for example, not only involves six or more months of physical rehabilitation and lifestyle chaos, but also is frequently complicated by blood clots that may travel to the lungs, kidneys, brain, liver, or intestines, or involve other serious surgical complications. More than 310,000 hip fractures were reported in North America in 2005 and each case cost at least $45,000 and involved considerable pain.
Dr. Robert Josse, Associate Physician-in-Chief, St. Michael’s Hospital and Professor of Medicine, University of Toronto, says that 20 percent of older patients die within three months of a fracture and 15 to 20 percent will not be able to regain their former independence and must be admitted to a nursing home. This crisis situation shows no signs of improving despite the millions of dollars being poured into pharmaceutical research and promotion. Perhaps what is needed is a fresh new approach.
The Other Side Of The Story
In the course of researching for this book, I found that every type of drug therapy has serious side effects. Some drugs work to protect the hip or the spine, but not for both of them. Medications for osteoporosis have been studied for anywhere from one year to ten years, and none have been studied for longer than ten years. Long-term effects of medications after that time period are simply unknown. No expert in the field knows how long the drugs should be taken and when they should be stopped. In addition, medication cannot be used for children, and younger adults, as they have not been studied in this age group. I also found out that loss of bone density with age is normal and does not automatically mean an increase in fracture risk. New Zealand researcher and author, Gillian Sanson says in her landmark book, The Myth of Osteoporosis, “Osteoporosis is thought of as a disease when in most cases, it is just a condition than can be remedied by a smart lifestyle makeover.” Furthermore,she states, “People are diagnosed with osteoporosis because they have low bone density, not because they have bone fractures. This occurs routinely despite the fact that BMD (bone mineral density) does not accurately identify men or women who will experience a bone fracture. A person with high bone density may go on to fracture, and another with low bone density may never fracture. Low BMD is but one of many risk factors of a disease that can be truly diagnosed only when there is a “fragility fracture”—a bone fracture resulting from low impact due to trauma. Calling low BMD osteoporosis is like calling elevated cholesterol heart diseases or calling high blood pressure a stroke.” Moreover, hip fractures in those aged 80 or over are a marker of accelerated wear-and-tear, of overall poor or frail health. In addition healthy women and men rarely die from hip fractures. In women who were mobile before a hip or pelvic fracture it is estimated that as few as 14 percent of their deaths werecaused or hastened by the fractures. Most factors that cause fractures in those 80 years of age or older are unrelated to low bone density, but due to severe falls after years of suboptimal nutrient intake. In Chapter 2, we note that science and technology have magnified the destructive impact of acidification of our air, oceans, soils and upon humans themselves. If we look more deeply into medical research we will find that underneath the many surface differences of diseases such as cancer, cardiovascular disease, stroke and osteoporosis is this question of both inflammation and maintaining an alkaline pH.
There are six core insights that I believe we must focus on to be able to avoid or reverse major illness including heart disease, mental decline and osteoporosis:
The good news is that by following the well-documented recommendations and step-by-step self-help action plan, outlined in Chapters 1 to 11 of this groundbreaking book, you can experience lifelong bone health naturally. It is only through major changes to our lifestyle including diet, exercise and stress reduction that we can truly hope to prevent and reverse osteoporosis. Even if you have the condition and experience a fragility fracture, lifestyle changes are the major preventative tactic and are at least as important, if not more important, than medication in any treatment management protocol. This book offers insight and hope that will allow you to actually prevent needless fractures, “dowager’s hump”, and loss of mobility or independence—and—even regain enough bone mass to take you out of the high-risk zone. Both bone health development and maintenance is natural and spontaneous when you follow this book’s simple but comprehensive program. I personally follow it! And perhaps mostimportantly, the life-saving information and guidelines provided in The Bone-Building Solution will keep your bones strong and even reverse bone-breakdown or osteoporosis, so that the need for prescription drugs may be eliminated. Naturally, people in their later years may need a medication to assist them, but the vast majority of us can naturally prevent, treat and reverse osteoporosis.
I present Chapters 12, 13 and 14 to you so you can fully understand the traditional medical approach that most physicians utilize, and see the promising alternative approaches doctors like me are utilizing with great results in people of all ages. No matter what positive changes or fine-tuning you decide to make in your diet, exercise, supplement and lifestyle, be sure not to pass an early judgement until you give yourself 6 full weeks to truly adapt and assimilate the changes. Remember, you are removing layers and years of eating habits and a lifestyle that may not have been good for your health. You are also acquiring new tastes, new foods and a better way of living. I have never met anyone who regretted trying the 6 well-publicized lifestyle makeover changes I have presented. I know, as a physician, osteoporosis is preventable. I also know that it has reversal potential. This book represents an invitation to take care of your own optimum well-being and to give you real hope that youcan have healthier bones, a stronger stature, better posture and more fluid biomechanical movement naturally, all-life-long.
The Proof Is In The Pudding
I thoroughly enjoyed Chapter 5 about the acid-alkaline effect our food choices have on the health of our brain, heart, bones, teeth and nails. To further emphasize the virtues of a natural food diet I would like to present the latest research showing the need to eat more vegetables, salads, berries, fruit, herbs, spices and “green drinks” to experience an alkaline biochemical functioning. While an internal alkaline balance is optimal, our biochemical functioning, daily stress of living, exposure to toxins and even the metabolism of food, produce a great deal of acidic by-products. For example, when we exercise or move we produce lactic acid and carbonic acid. Lactic acid and carbonic acid in turn are broken down—carbonic acid to carbon dioxide which we exhale and water which we excrete. Phosphoric acid and sulphuric acid are likewise produced from the metabolism of the phosphorus and sulfur contained in many foods such as meats rich in sulfa-amino acids. To regain the life-supportingalkaline state, acids from all sources must be buffered or neutralized through combination with alkaline minerals. Acid-forming elements in our food include phosphorus, sulfur, chlorine, iron and iodine. Foods in which these elements predominate leave an acidic residue when metabolized. The alkaline minerals are calcium, potassium, sodium and magnesium that can form bicarbonates to neutralize excess acids by acting as “acid sponges”. Dr. Anthony Sebastian and colleagues at the University of California in San Francisco, recently presented evidence of the need for alkaline/acid rebalancing. In a groundbreaking study reported in the Journal of Clinical Endocrinology Volume 90, in February 2005, they looked precisely at postmenopausal bone loss and its relation to alkaline/acid balance. Their first observation was that postmenopausal women in North America generally exhibit a low level acidic state, rather than the ideal low level alkaline state, due to acids produced in metabolizing ourtypical high fat, sugar, processed grains and animal protein diet. Then they speculated that a lifetime mobilization of alkaline minerals from bone, to neutralize this acute acidic condition, would contribute to a decrease in bone mass. This bone loss, they suggested, could be reduced and bone formation enhanced by neutralization of these acids and subsequent sparing of the body’s alkaline minerals. Research shows, as you eat more animal protein (meat), your acid load increases. Their research findings validated these speculations. Women who daily consume the Standard American Diet (SAD), containing some 80 grams of acidifying animal protein, were given an alkali in the form of potassium bicarbonate. This alkalinizing “acid sponge” neutralized internal, excessive acid production, which led to a decrease in calcium and phosphorus excretion, and stimulated new bone formation, and a reduction in the rate of bone-breakdown. Facilitating a return to the normal alkaline state sparedbone-building minerals and enhanced bone health and bone mineral density (BMD).
Important Note On Protein Consumption And Calcium Elimination In your body, calcium and protein have a see-saw relationship. As acidifying animal protein levels rise, the calcium content of your bones goes down. Excess animal protein above 60 grams a day for the average woman and 90 grams a day for the average man, raise acid levels that can lead to kidney stones, kidney injury and accelerated bone-breakdown. John McDougall, M.D., author of The McDougall Program for Women, says that eating excess animal protein is the human body’s “equivalent of acid rain”. You need to include some vegetable protein in your daily diet and lots of brightly colored produce, to buffer the acids from eating animal protein.
Stages Of Life And Weak Bone Prevention The decade between 20 to 30 is the age of maximum bone-building and developing peak bone mass. A healthy lifestyle is essential, with core exercise and a comprehensive food-based, bone-building supplement. 30 to 40 is the “green light” decade. This is a pivotal age, since the average age at which you begin to lose bone is age 34. After that, you lose one percent bone mass per year. It is important to maintain a good exercise regimen and to improve nutrition and take a good food-based, bone-building nutritional supplement. This is a critical decade for maintaining maximum bone mass, bone strength and bone structure. From 40 to 50 is the “orange light” decade of vulnerability in which you can have more stress and at the same time let exercise and nutritional regimens slide. Vigilance is critical at this time to pay attention to diet, stress reduction, a bone-building supplement and core exercise for both strength and balance—these are all vitallyimportant for your future posture and structure. 50 to 60 is the “red light” decade of caution. This is the wakeup call decade. You have to work consciously on weight training, core exercise, eating an alkaline diet and taking a high quality bone-building supplement each and every day. Stress reduction and deep sleep are important. The decade of 60 to 70 is a time when you want to retain your maximum bone strength and function. The same program that will stop bone loss will also help lower your high risk of stroke, cancer and heart disease. Optimal health programs are essential to longevity. 70 to 80+, primary attention must be given to fall prevention, building strong muscles and maintaining bones. It is imperative that you fall-proof your home to ensure that there are no obstacles that could cause a fall. Daily, walk as much as possible and use a food-based, bone-building supplement. Believe it or not, bones are much like your muscles. The more you use them, the stronger they become.The opposite is also true. If you do not walk enough, but sit around to rest your weary bones, they become weaker and much more prone to fracture.
PUT YOUR BONES TO THE TEST
Who Is At Risk For Weak Bones? If you have a family history of osteoporosis, then, as with so many conditions, your risk of experiencing it is greater. If your mother or father had a broken hip, this suggests that your risk factor would double. It is estimated that if someone in your immediate family has primary osteoporosis, you have between a 60 to 80 percent chance of developing the disease yourself. Why is it important to assess your family history? Because when you understand that your risk factor is high, you know how important it is to get a BMD test and stay wisely on top of your optimum bone health, long before you have any signs of trouble. According to the American and Canadian Medical Associations, between 20 and 30 percent of women who have gone through menopause have osteoporosis, and another 3 percent have low bone density. Why do women get more osteoporosis? In part, the risk is due to normally thinner bones, and partly because the loss of estrogen at menopauseaccelerates bone loss, especially for the first five to seven years after menopause begins. However, it must be emphasized that lower bone density is a normal part of aging and by itself does not lead to fracture. That is why improving your diet, maintaining core exercise levels for strength and balance, and daily using a “molecular targeted” bone-building supplement, as we age, is so critical to bone health mobility and independence. Looking at the statistics in a different way allows more hope for men and women. Eighty-five percent of people aged 50, with a life expectancy of 80 years, will not suffer a hip fracture. Furthermore, as mentioned previously, for those in good health prior to a hip fracture, the injury rarely leads to death. In a nutshell, living the “cell friendly” lifestyle detailed so well in this book and following the ancient rules of color coded eating that Sam Graci emphasized in Chapter 4, will preserve and maintain bone health, even if a weak bone relatedfracture should occur in your lifetime.
Men And Children Are Also At Risk—Many Do Not Know It Although many osteoporosis sufferers are women, men and children are also at risk of osteoporosis or weak bones. In fact, 4 million men in North America have osteoporosis, and one in two men older than age 50 will have an osteoporotic-related fracture in his lifetime. It is called a “silent epidemic” that actually begins in our 20s and for some even earlier in their teens. Osteoporosis begins to affect men about ten years later than it affects women. And because both men and women are living longer, researchers and doctors anticipate more people will have hip fractures in the future. In fact, by the year 2020 researchers project that men will have one half of all hip fractures in North America. Men must become bone wise. Because osteoporosis apparently becomes an equal opportunity disease as you age, you may be curious as to when men should start having bone mineral density scans. All men older than 70 need a baseline scan, as wellas men under age 60 who have risk factors, such as long-term corticosteroid use or use of drugs to treat prostate cancer.
Lost In Translation Your bone density potential is partially determined by hereditary factors, and partially by lifestyle and environmental factors. Many bone experts are especially concerned that today’s children are going to suffer from osteoporosis at alarming and increasing numbers, due to a number of factors. Remember—children, preadolescents and teens are at the most critical age for building healthy bones. Why are today’s children putting themselves at a higher risk level for future osteoporosis?
Prevent A Future Shock In Your Children’s Lives The 2006 television series, Honey We’re Killing the Kids, counsels young preadolescents and their parents who are very sedentary and living almost exclusively on processed, acidifying fast foods. A computer program projects what the children will look like at the ages of 15, 25, 30, 35, 40 and 50. In every case the children and parents were shocked to see that their skin quality, hair quality, physical appearance and overall health would deteriorate to such a degree if their poor lifestyle habits continued. Obviously, there are some risk factors you cannot do much about, but there are others that you can. I’m not suggesting that it is easy to change the lifestyle patterns of a lifetime, or that you can simply stop taking necessary medications because they enhance your risk of developing osteoporosis. It is important to be aware of these critical factors so that you can intelligently deal with them as effectively as possible. Here is alist of some of the most important risk factors you can change with simple, effective, and safe lifestyle adjustments, proper exercise and a smart supplement action plan, regardless of your age.
11 Risk Factors You Can Change
For now just remember that even walking as exercise, combined with a modest amount of weight training, can go a long way toward saving your beautiful bones. Please see Chapter 6 of this book, Ramp Up Bone-Building Metabolic Exercise, for suggestions and ideas.
Smoking Smoking is a real problem when it comes to osteoporosis. Estrogen helps prevent osteoporosis by inhibiting the action of osteoclasts, the cells that break down and clear away old bone. Smoking has the effect of inactivating estrogen, leaving the smoker with what amounts to an estrogen deficiency. Men and women who smoke usually reach andropause or menopause before men and women who don’t. Not only that, smokers are often less physically active than non-smokers, which again increases the risk of developing osteoporosis.
Alcohol Here’s what we know about the effects of alcohol on healthy bone structure and function:
Caffeine Since caffeine is a diuretic to the kidneys, it may increase the amount of calcium excreted in urine. It is a stimulant to the brain and heart, as so many of us know from experience when we find that we can’t really get going until after we’ve had our first cup of coffee in the morning. Caffeine is most often found in tea leaves and coffee beans, and as with alcohol, it is fine when used in moderation, but can have a negative effect on our bones when we overdo it. Two cups daily of black, organic coffee is the maximum acceptable. Make sure that if you are drinking decaffeinated coffee that it is a water based decaffeination process rather than one using chemicals. Every day, we lose between 100 and 250 mg of calcium through the kidneys into the urine. My feeling is that anything that increases calcium loss in the urine, which caffeine does, simply leads to increased calcium deficiency, and so should be limited as much as possible. Dr. Robert Heaney, an osteoporosis specialist,and his associates at Creighton University in Nebraska reported the results of a study in which sixteen people were given four 100 mg caffeine tablets a day for nineteen days. All of the people had calcium intakes of at least 600 mg per day. They also took a bone-building supplement.. They concluded that 400 mg of caffeine per day was very helpful, if the people were also getting at least 600 mg of calcium in their diets each day. They also suggested that the increased loss of calcium in the urine from drinking caffeinated coffee may have occurred only in the first three hours after drinking the coffee, and did not persist for the rest of the day. Dr. Robert Heaney reported in 2002 in the journal Food and Chemical Toxicology that there is no evidence of a detrimental effect on bone health—from coffee and tea—as long as an individual meets daily calcium, vitamin D and micronutrient requirements. Limit your coffee consumption to two cups a day—that’s cups (5 ounces), not mugs (10ounces). Eliminate pop from your diet and that of your children’s. Remember that every can of acidifying pop contains 8 teaspoons of sugar in addition to caffeine. The phosphoric acid in soft drinks harm the micro-architecture of your bones, and have especially negative consequences for children’s health and their future bone development.
Low Levels Of Calcium And Vitamin D It should be pretty clear by now that it is important to eat lots of green, leafy vegetables, “green drinks” and fat-free dairy products like organic yogurt every day, so you can get a jump start on overcoming the calcium deficiency that more than 50 percent of all North American men and women have. To maintain optimum calcium levels easily, use a food-based, bone-building supplement containing calcium, magnesium, vitamin K1, probiotic cultures and vitamin D3.
Low Body Weight If you are a small-boned, lightweight person, then your risk of developing osteoporosis is particularly high. Several studies suggest that if you weigh less than 130 pounds for women or 150 pounds for men, you are especially susceptible to developing osteoporosis. The point is that you can be too thin, which for the majority of women are somewhat of a relief. In fact, a risk factor for osteoporosis is that you weigh the same as you did when you were 25. Appropriate body weight, as well as weight-bearing exercise, goes a long way toward protecting our bones. If you are underweight for your height and frame, I’d suggest you start doing something about that now. Healthy, calcium rich diet; a bone-building supplement and exercise are just what the doctor ordered.
Some Medications Some medications interfere with calcium absorption, or bone formation and remodelling, thereby leaving you more susceptible to developing osteoporosis. This can create a tricky situation, since these medications can be vitally important to your health. If you are taking one of these medications or are planning to do so, be sure to let your doctor know about your concerns relating to their impact on osteoporosis. Here are some medications to be aware of:
A High Salt Intake Destroys Bone Integrity Sodium, as found in salt, is a mineral of great importance to overall health. Yet, as with sugar and phosphorus, we consume far too much of it. Today North Americans consume much more salt than is desirable. Even though the U.S. and Canadian governments since 1977 have been recommending limiting salt intake to 2,000 mg per day, our consumption still averages over 8,000 mg per day. Don’t be deceived into thinking your salt intake is low just because you do not use a saltshaker. The salt in our diet comes mostly from processed foods—and lots of it. Salt is second only to sugar as the most popular food additive. A three piece fast food fried chicken dinner alone may contain 2,000 to 2,500 mg of sodium; one can of soup could have 3,000 mg of sodium; and one cup of canned tomato juice has as much as 500 mg of sodium chloride. Remember, restaurants use a lot of table salt in their food preparation. Highly processed table salt, sodium chloride,causes the body, through the kidneys, to lose calcium in the urine, contributing greatly to osteoporosis. Osteoporosis means “porous bones.”
Sugar, High-Fructose Corn Syrup And Artificial Sweeteners Are Harmful For Your Bones Sugar, sweet treats, alcohol and stimulants are ultimately counterproductive to your physical and bone-building well-being. While they initially cause you to feel stimulated, shortly afterwards you are drained and start to crave more sugar. Sugar contributes to acidifying the system, overproduction of insulin (which can eventually lead to diabetes) and hormonal imbalance. So there is a short-term gain for a long-term price. Sugar has always been available in natural sources from fruit, with its slow-releasing fructose balanced by fiber content that gives our bodies small, constant spurts of glucose, the primary fuel in our bloodstream. Terry Grossman, M.D., an anti-aging physician and co-author of Fantastic Voyage, states, “The two chemicals that will age you quicker than anything else are cortisol, a by-product of stress, and elevated insulin, which peaks with sugar consumption.” Sugar promotes growthof a broad variety of pathological cells, including the yeast candida albicans and fungal infections. Sugar is a “naked carbohydrate”, that was introduced to North America by Christopher Columbus in 1493. It has many names, most of which end in -ose, e.g. fructose, glucose, maltose and sucrose. Do not use suspect, manufactured fructose added as a sweetener to foods, even healthy foods, since it may appear to support the initiation of cancer. Healthy sweeteners include stevia and agave syrup.
One Study Links Sugar to Increased Risk Of Cancer Findings from the Korean Cancer Prevention Study, published in the January 12, 2005 issue of the Journal of the American Medical Association, finally revealed a direct correlation between elevated blood sugar levels and diabetes and the risk of developing and dying from cancer. Sugar and sweeteners are acidifying. Tumors are primarily obligate glucose (sugar) metabolizers, meaning they require sugar for survival. Even though the brain normally uses high amounts of glucose, a hepatoma (a tumor of the liver), as an example, consumes roughly as much glucose as the brain. Many North Americans continuously satisfy cancer’s appetite by ingesting as much as 295 pounds of sugar a year. Nobel Laureate Otto Warburg, Ph.D., discovered in 1955 that cancer cells use glucose for fuel. But, acidifying glucose accomplishes another strategic manoeuvre that favors cancer growth: it immobilizes and depresses the abilities of the immune system; it can alsocause bones to lose calcium rapidly. A lifestyle and diet that diligently eliminates all food with added sugars or synthetic sweeteners, deprives cancer of its primary energy supply and boosts the reliability of the immune system and maximizes bone-building functions.
Good Balance And Core Strength—Can Prevent Falling Osteoporosis can make bones vulnerable—falls can break them. Almost 90 percent of osteoporosis-related hip fractures, and more than 90 percent of pelvic and hipbone fractures, and 50 percent of spinal fractures, result from falls. Surprisingly so, good balance depends on your vision. Therefore, do some walking or balancing exercises each day with your eyes closed, to train your brain to keep you upright and steady. People who are physically fit and active have better balance and far fewer bone fracturing falls in their later years. Have your vision and hearing tested annually. Fall prevention techniques may be better than medications at reducing the death rate from hip fracture. Research shows that a fall to the side, as opposed to forward or backward increases the risk of hip fracture by about six times, and is considered a much greater risk than lower bone density for hip fracture. Mary Tinetti, M.D., of Yale University took a groupof 300 women and men aged 70 or older. Half the group, the control group, received no special care. The other half learned exercises to improve their strength, balance and coordination—which resulted in 48 percent fewer falls—a very significant reduction for a group at such high risk. Western medical researchers are beginning to appreciate what Eastern medical researchers have known for many years—that Tai Chi, Qigong and hatha yoga can dramatically improve your balance. Poor balance is not only a concern for us in our senior years, but an issue for us in our younger years because we are all vulnerable to falls. It is estimated that 50 to 60 percent of falls happen in the home and 85 percent of those are caused by common “domestic hazards” like throw rugs, extension cords, slippery floors, dim lights or clutter on the floor. Give your home a serious safety check-up and immediately correct any problems you find. Follow the core strengthening program in Chapter 6, Ramp Up Bone-BuildingMetabolic Exercise, to feel more secure and steady on your feet, improve your muscle and bone strength, enhance balance and significantly increase your fluid range of motion for a lifetime.
Osteoporosis Is Not An Isolated Disease Osteoporosis is not a dreadful disease that randomly strikes some of us. Weak bone structure does not happen without a cause and that cause is often associated with many other health related problems like a poor diet, a lack of proper exercise, pop and sodas, acidifying junk food, excessive stress, smoking, some medication use, alcohol abuse and toxic exposure. I collectively call them—bone-depleting factors. Osteoporosis is a very complicated problem which Western medicine has tried to make very simple. Our unhealthy lifestyle habits deplete our bones of their precious stores of life-supportive minerals. The ultimate price we pay for excesses in these destructive modern day, “grab-and-feed” habits—is osteoporosis. In reviewing the available anthropological data from around the world, I discovered that osteoporosis occurs in some countries more than it does in others. Canada and the United States have some of the highest osteoporosis rates in the
There are several types of BMD tests. All the tests are simple and painless.
Bone Testing Options—What Type Of Test Should You Have? Once it has been determined that a bone density test is needed, your doctor must figure out what test to use. There are several types of bone density measuring devices. It’s important to understand the advantages and disadvantages of the different measurement techniques.
What Bone Testing Measures Bone density tests only tell you one risk factor for osteoporosis—that is a decreased bone density. The larger the amount of mineral content in the bone, the higher is the bone density. It is the combination of mineral deposits and the micro-architectural structure that give bones their overall strength. There is currently no test that can measure bone strength and give you information about the microstructure of your bone.
Dual X-Ray Absorptiometry (DXA) The most common method for determining your bone density is the central dual X-ray absorptiometry technique (central DXA). This machine is most often located in hospitals and radiology centers. Anyone living in an urban or suburban area will have access to one of these machines. You lie comfortably on a scanning table. When your spine is measured, as shown above, your legs are positioned on a firm pad to help flatten out your spine. For measurement of your hipbone, you lay your legs flat on the table. During the test, the scanner moves back and forth over your body. It can measure bone density in the hip, spine and forearm. They are important sites where fractures have the most serious consequences. The current test of choice is dual X-ray absorptiometry (called DXA or DEXA for dual energy X-ray absorptiometry), and it is widely available. The hip and spine measurements are the most common procedures. The greater your risk for osteoporosis, the moreimportant this information is for you. The small amount of radiation involved in a bone density scan is one tenth of a chest X-ray. A smaller version of the DXA can measure bone density in the hands and the heel. The test takes two minutes, and the small machine can be used in doctors’ offices, which makes it more convenient for many people. It is very important to have your bone density scans repeated on the same machine if you are comparing them. Various machines are not standardized; so comparing a reading obtained on one manufacturer’s machine to that obtained on another, is not accurate.
Ultrasound Densitometry Another commonly available testing option is ultrasound. This technique involves no radiation. Ultrasound testing is already available in many doctors’ offices. The ultrasound assesses bone in the heel, tibia, patella or other peripheral sites where the bones are relatively close to the surface of the skin. It is a much underutilized screening technique. According to the National Osteoporosis Foundation’s Physicians Guide, although the measurements are not as accurate as DXA or SXA (single X-ray absorptiometry), they appear to predict fracture risk as well as other measures of bone density. A study of 149,524 postmenopausal women suggested that ultrasound and peripheral BMD are accurate in predicting fracture. Those with low bone density in the heel, forearm, or finger had a twofold increased risk of fracture within one year. You must still be cautious, since this method of measuring bone density includes the same standard deviation problems as those of the DXAscan. It can classify a large number of people at high risk with too many false positive readings. Unfortunately, ultrasound can’t check bone density in the spine and hip. The site most commonly measured is the heel; other bones in the lower leg and hand can be checked too. The results reflect not only density but also properties of collagen in the bone. While this information is helpful because the results are strongly correlated with fracture risk, it’s not a substitute for direct measurement of hip or spine bone density with DXA. However, it is a quick and inexpensive way to check for bone loss and will let you know if you are in a high-risk category and need to get a DXA scan.
How The Tests Work DXA uses a technique called densitometry or X-ray absorptiometry; the machine passes an X-ray beam through an area of bone. Ultrasound testing uses sound waves instead of X-rays. Radiation (or sound waves) are absorbed by the bone—the denser the bone, the more it absorbs. The machine’s detectors translate absorption information into a measure of bone density. The “dual” in dual X-ray absorptiometry (DXA) refers to the use of two different X-ray beams, which enables the machine to distinguish between bone and the soft tissue (e.g., muscle, fat) covering it. That’s why DXA can measure density of the hip and spine bones, even though they lie deep inside the body. Tests that use just a single beam can only measure bones that are just under the skin, such as the bones in the hand, wrist, and heel.
Single X-Ray Absorptiometry (SXA) Now that DXA is available, SXA—which can’t check spine and hipbones—has been phased out. SXA measures bone density in the fingers, wrist and heel. Those results correlate strongly with hip and spine density, so the test remains a good general indicator of bone health.
Radiographic Absorptiometry (RA) Radiographic absorptiometry (RA) is a special type of X-ray. It measures bone density in the hand, which is closely correlated with hip and spine density. The chief advantage of RA is low cost. Also, nearly any X-ray machine can be adapted for RA. This makes it a valuable screening tool for people without easy access to DXA, such as those who live in remote rural areas.
Computerized Axial Tomography (CT or CAT Scan) CT scans are used mainly in research. But they can be helpful when other tests aren’t available, or in special situations. DXA, SXA, X-ray and RA all produce a two-dimensional image of the bone. CT also uses an X-ray beam, but it can create a three-dimensional image that can be important when a man or woman appears to be losing significantly more trabecular (the spongy inner part of the bone) than cortical bone (the hard outer part of the bone). In such a case, a CT scan would allow separate examination of the trabecular bone in the center of his or her spine. Please see Chapter 2 of this book for the radiation levels involved in CT scans.
X-Ray and Radiographs An X-ray based technique in which the hands are measured alongside an aluminum wedge can also be used to measure density. Results are sent to a central processing center for computer determination of bone density. This technique does require central processing, so results may not be available as soon as the X-ray is completed.
The Limitations Of Bone Density Measurements Bone mineral density testing has many limitations. The sites most commonly measured are the spine and the hip. But, your bone density can vary throughout the 206 bones in your skeleton. It is hard for me to conclude a patient has osteoporosis when one bone, for instance your hip, records low bone density, when the spine may be normal, or vice versa. The National Women’s Health Network publication, Osteoporosis Fact Sheet, suggests that a better evaluation of bone density is obtained by comparing a person’s bone density to that of other fracture-free, healthy people your age. Worrisome for me, is that half of all people are shown to have low bone density on a dual X-ray absorptiometry test (DEXA), the preferred medical procedure for osteoporosis testing. These scans can detect if your bone density is lower than that of other people your same age and sex, but they cannot predict if you will suffer a fracture. Bone density measurements compare
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