Let’s take a closer look at the anatomy of osteoporosis. A cross section of bone is usually comprised of a ring thick, strong, cortical, or compact bone, and the lighter trabecular, or spongy, bone that is essentially a collection of struts and arches. The spongy bone normally provides strenth without adding a lot of weight. Osteoporosis affects both types of bone, opening and connecting the spaces in spongy bone until it lacks mechanical strength, and eating into the normally dense compact bone. In severe cases the outer ring of compact bone is breached.
While there are no simple symptoms of porous bones, there can be disastrous results from this disease. The risk factors are often simple things, such as being a woman, or being Caucasian, Asian, or Hispanic/Latino, although African Americans are also at risk. Women are more prone to fractures than men in general, because they tend to have lighter bones to begin with. Older age, family history of osteoporosis, self-history of broken bones (especially hip fractures), being small and thin, and men and women having low levels of estrogen or testosterone may be risk factors you cannot control. Young women athletes with irregular menses may be at elevated risk as well. The sex hormone estrogen normally inhibits the activity of bone reducing osteoclasts. Menopause reduces estrogen levels, allowing the osteoclasts to kick into dangerous overdrive.
Risk factors you can change include: poor diets that lack calcium and vitamin D or have excessive amounts of protein, sodium and caffeine (including that found in soda); being inactive; smoking, which also reduces estrogen levels; drinking alcoholic beverages to excess, and taking certain medications such as steroid medications, some anticonvulsants and others. Certain diseases and conditions such as anorexia nervosa, rheumatoid arthritis, gastrointestinal diseases and others can also lead to an increased risk of osteoporosis.
With all these risk factors, and a lack of symptoms until something breaks, how can you know in advance if you are at risk for fractures from osteoporosis? You can see your primary care physician for a Bone Mineral Density (BMD) test. Studies indicate that there is a strong correlation between low bone density and risk for a fracture in the near future. BMD tests can be performed a few different ways, but there is some risk of getting a false positive with this type of test. A more detailed osteoporosis test lab workup would include a variety of tests including blood and urine tests for several hormones, phosphate, and calcium levels. These tests determine whether osteoporosis may be caused by a secondary disorder such as renal or hepatic failure, anemia, acidosis, hypercalciuria, or abnormal calcium or phosphate levels. Another test can check levels of bone building osteoblasts. Tests for vitamin D deficiency may also be recommended.
Your test results may indicate that you have a normal bone density, or that you are suffering from lower bone density that can fall in a range from the milder osteopenia to full blown osteoporosis. By itself, osteopenia does not indicate a loss of bone density. Rather, you may simply have always had less dense bones! Like osteoporosis, osteopenia is lower than peak bone density. Osteopenia may be caused by a variety of medical conditions. If you are diagnosed with osteopenia, your doctor may recommend that you start taking precautions to inhibit the onset of osteoporosis. These are often the same things you would do to combat the effects of osteoporosis, discussed next.
While no cure for osteoporosis exists, the good news is that there are treatments available. Most are for postmenopausal women, or for men. Women who are no more than ten years beyond menopause may choose to take estrogen supplements. Anyone undergoing treatment for osteoporosis should get additional testing annually to check progress. A better idea is to prevent osteoporosis early in life. A brief scan of the risk factors will indicate a few suggestions: get plenty of calcium and vitamin D; do not smoke; do not drink to excess. Regular weight bearing exercises will increase your bone density, and muscle-strengthening exercises will help, too. Drinking fluoridated water can help strengthen your bones. Preventative steps are especially important for children and people under thirty years old, because the bones are still developing quite a bit until then. If you get a BMD test early on, you will be in a better position to determine if you need to change your habits or begin taking medication.
Calcium plays a strong role in the remodeling of bone structure. Its presence inhibits the release of parathyroid hormone, or PTH. PTH is released when blood calcium levels are low, which stimulates osteoclasts to break down bone and release stored calcium. (Calcium levels must remain high enough in the body to participate in muscular contractions and nerve impulses.) Calcium is readily available in a variety of food sources, from dairy products and vegetables to nuts and grains. While calcium supplements are available, not all are off sufficient quality to be beneficial. If you are trying to add more calcium to your diet, it is best to take in calcium at more than once time during the day, because the body immediately discards surplus calcium. Dietary protein and caffeine can negligibly increase the loss of calcium through urination. People with kidney problems must be careful of their calcium intake, however, as excess calcium can lead to the development of kidney stones.
Vitamin D is paired with calcium in the recommendations as it enhances adsorption. One of the best ways to get an adequate intake of vitamin D is to spend some time in the sun without sun block every day. In cases where this is not practical for medical or geographic reasons, vitamin D fortified foods or vitamin D supplements can be consumed.
What sort of weight bearing exercise is required to have an impact on bone health? It can be as simple as walking! A walking program can be instated at almost any age, and is useful before and after diagnosis of osteopenia or osteoporosis. Lifting weights and participating in Tai Chi are also recommended activities. Our bone structure is constantly changing in response to stimuli. Thus, weight-bearing exercises tell your bones that you need stronger bones to resist the effects of gravity. When your workout includes muscle-strengthening exercises, the bones respond to bulkier muscles by becoming stronger themselves.
In general, you can prevent the onset of osteopenia or osteoporosis by eating well, maintaining healthy habits, and getting load-bearing exercise such as walking from a young age. Lacking things that inhibit osteoblasts from working or having too many things that encourage osteoclasts causes an overall loss of bone density over time. Risk factors for osteoporosis are well known, and there are a variety of tests to diagnose the condition. There are various things you can do to treat osteoporosis. Treatment included lifestyle changes as well as medicinal approaches. Osteoporosis prevention and testing should become a part of your complete medical checkup.
References
Arnheim, Daniel D., and William E. Prentice. Principles of Athletic Training, 10th ed.. New York: McGraw-Hill Higher Education, 2000.
"Bone anatomy in osteoporosis". Up to Date Inc.. November 2, 2009 .
Marieb, Elaine N., and Katja Hoehn. Human Anatomy and Physiology, 7th ed.. New York: Pearson Education, Inc, 2007.
"Ossification: An Introduction to Bone Formation, Growth, and Repair". Province of British Columbia Ministry of Advanced Education, Training and Technology . November 2, 2009 .
"Osteopenia - Overview". Web MD, Healthwise, Incorporated. November 3, 2009 .
Ott, Dr. Susan. "Osteoporosis and bone physiology". University of Washington Department of Medicine. November 2, 2009 .
"Osteoporosis Fast Facts". National Osteoporosis Foundation. November 2, 2009 .
Thomasen, Eivind, and Rachel-Anne Rist. Anatomy and Kinesiology for Ballet Teachers. Alton, Hampshire: Dance Books, Ltd, 2005.
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