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Osteoporosis: The Bone Thief
Helen grew up on a dairy farm in the Midwest. She drank 3 glasses of milk a day as a child. After high school she began work as a secretary in a local law office where she spent her entire career. Helen never jogged, walked as exercise, or played tennis. She went through menopause at age 47. Shortly before retirement at age 61, she slipped on a small rug in her kitchen and broke her hip. After Helen recovered, she needed a cane to walk.
Helen had osteoporosis, but she didn't know it. Osteoporosis is a disease that thins and weakens bones to the point where they break easily—especially bones in the hip, spine (backbone), and wrist. You can lose bone over many years. Because you may not notice any symptoms until a bone breaks, osteoporosis is called the "silent disease."
Bone is living tissue. Special cells called osteoclasts are constantly breaking down old bone as other cells known as osteoblasts are replacing it with new tissue. As people age, more bone is broken down than is replaced. The inside of bone normally looks like a honeycomb. In osteoporosis the spaces in this honeycomb grow larger because much more bone is destroyed than is replaced. This makes your bones weaker.
Experts do not fully understand why this happens. They do know that after women go through menopause, levels of the female hormone estrogen are much lower. These lower hormone levels can lead to bone loss and osteoporosis. Other causes of this disease include too little exercise and a diet too low in calcium and vitamin D.
Who Gets Osteoporosis?
More than 10 million Americans have osteoporosis. Eighteen million more have lost enough bone to make them more likely to develop this disease. More than 80% of these 28 million are women. One out of two women and one in eight men over age 50 will have an osteoporosis-related fracture during their lives. White and Asian women are most likely to get osteoporosis. Women who have a family history of the disease, an early menopause, or small body frames are at greatest risk.
Osteoporosis is not just an "old person's disease." It can happen at any age, but the risk grows as you get older. After age 30, bone loss begins to occur very slowly. In women the rate of loss increases for several years after menopause, then slows again, but continues. As men age, they do not have the same kinds of striking hormone losses as women do in mid-life. In men the drop occurs more slowly. But, by age 65 or 70 men and women are losing bone at the same rate.
How Do I Know If I Am Losing Bone?
Losing height or having a bone break easily is often the first sign of osteoporosis. Bone density is a term that describes how solid your bones are. Ordinary x-rays do not show bone loss until a large amount of bone density is gone. The most exact way to measure bone density is by a DEXA-scan (dual-energy x-ray absorptiometry). This is done on the whole body. Ask your doctor about this test if you think you are at risk for osteoporosis or if you are a woman around the age of menopause or older.
The DEXA-scan can show whether you are at risk for a fracture. If you have already broken a bone and your doctor thinks you might have osteoporosis, the test can confirm the diagnosis. If more than one test is done at least a year apart, your doctor can compare the test results over time. Then he or she can see if the treatment has succeeded in slowing your bone loss.
The test results are reported as a number. If your doctor says your result was -2.5 SD (standard deviation) or more, this means you have osteoporosis. A test finding of -1SD to -2.5SD means you have some bone loss. This is known as osteopenia, and you are at risk of developing osteoporosis.
Can I Prevent Bone Loss?
Osteoporosis is preventable. A diet that is rich in calcium and vitamin D and a lifestyle that includes regular weight-bearing exercise are the best ways to prevent weakened bones in later life.
Calcium. Getting enough calcium all through your life helps to build and keep strong bones. In 1997 the National Academy of Sciences (NAS) suggested that people from age 31 to 50 get 1000 mg (milligrams) of calcium each day. People over 50 should get 1200 mg daily. To do this, make foods that are high in calcium part of your diet. Some healthy foods that have a lot of calcium are:
- Low-fat dairy foods such as cheese, yogurt, and milk
- Canned fish with bones you can eat, such as salmon and sardines
- Dark-green leafy vegetables, such as kale, collards, and broccoli
- Calcium-fortified orange juice
- Breads made with calcium-fortified flour
Three to four servings each day from the dairy group will give you about 1200 mg of calcium. A serving is 1 cup of milk, pudding, or yogurt; 1-1/2 ounces of cheese; or 2 cups of cottage cheese. Try to use low- or non-fat foods.
If you think you need to take a supplement to get enough calcium, check with your doctor first. Calcium carbonate and calcium citrate are good forms of calcium supplement. Be careful not to get more than 2000 mg of calcium a day very often. That amount can increase your chance of developing kidney problems.
Vitamin D. Your body uses vitamin D to absorb calcium. Being out in the sun for a total of 20 minutes every day helps most people's bodies make enough vitamin D. You can also get vitamin D from eggs, fatty fish, and cereal and milk fortified with vitamin D, as well as from supplements. According to the NAS, people age 51 to 70 should have 400 IU (international unit) each day and those over 70 should have 600 IU. More than 2000 IU of vitamin D each day may cause harm to your liver and even lower bone mass.
Exercise. Exercise makes bones and muscles stronger and helps prevent bone loss. It also helps you stay active and mobile. Weight-bearing exercises, done three to four times a week, are best for preventing osteoporosis. Walking, jogging, playing tennis, and dancing are all good weight-bearing exercises. Strengthening and balance exercises may help you avoid falls and lessen your chance of breaking a bone.
There is no such thing as being "too old" or "too frail" to do some sort of exercise. You might want to check with your doctor before starting a vigorous exercise program if you are a man over 40 or a woman over 50 or if you have a chronic condition, a family history of certain health problems, or any other concerns.
Medication. Some medicines can cause loss of bone mass. These include glucocorticoids which are used to control diseases such as arthritis and asthma, some antiseizure drugs, certain sleeping pills, some hormones used to treat endometriosis, and some cancer drugs. An overactive thyroid gland can also be a problem. If you are taking these medicines, talk to your doctor about what can be done to protect your bones.
Other Lifestyle Prevention Steps. Avoid smoking. Smoking causes your body to make less estrogen which protects the bones. Also limit how much alcohol you drink. Too much alcohol can damage your bones, as well as put you at risk for falling and breaking a bone.
How Is Osteoporosis Treated?
Treatment of osteoporosis aims to stop bone loss and rebuild bone. Along with making lifestyle changes, there are several medication choices. Some will slow your rate of bone loss, and others will actually rebuild bone. These are:
- Estrogen. Doctors sometimes prescribe estrogen to replace the hormones lost during menopause, to slow the rate of bone loss, and to increase bone mass in the spine and hip. When estrogen alone is used, this treatment is called estrogen replacement therapy (ERT). Post-menopausal women who still have a uterus and who choose to take estrogen should receive hormone replacement therapy (HRT), taking both estrogen and progestin. Experts do not know all the risks of long-term use of these hormones. Each woman should discuss possible benefits, risks, and side effects of ERT or HRT with her doctor.
(NOTE: There are new facts about estrogen/progestin hormone therapy, July 2002. For more information see http://www.nhlbi.nih.gov/whi/hrtupd/ep_facts.htm.
- Raloxifene. This new drug is approved to prevent osteoporosis. It is known as a SERM (selective estrogen receptor modulator). Like estrogen, this SERM prevents bone loss, but may cause blood clots in some women. Unlike estrogen, it may cause hot flashes, but should not increase your chance of developing cancer of the endometrium (the lining of the uterus or womb).
- Alendronate and risedronate. These medicines are bisphosphonates, drugs that slow the breakdown of bone and may even increase bone density. They can lessen your chance of breaks in the spine and hip. Side effects may include nausea, heartburn, and pain in your stomach, muscles, or bones. These drugs must be taken in a certain way—when you first get up, before you have eaten, and with a full glass of water. You should not lie down or eat for at least one-half hour after taking the drug.
- Calcitonin. This is a naturally occurring hormone that increases bone mass in the spine and may lessen the pain of fractures there. It comes in two forms—injection or nasal spray. The injection may cause an allergic reaction and has some unpleasant side effects. The only side effect of the nasal spray form is a runny nose in some people. It is most useful for women who are 5 years past menopause.
- In the future. Other SERMs and bisphosphonates are being studied as improved treatments for osteoporosis. Also promising as possible therapies are sodium fluoride, parathyroid hormone (PTH), and some forms of vitamin D.
What About Falls?
When bones are weakened by osteoporosis, a simple fall can cause a fracture or break. This can result in a trip to the hospital, surgery, and possibly a long-term disabling condition. Osteoporosis is the cause of 1.5 million fractures each year. This includes more than 300,000 hip fractures. These fractures may put an end to independent living for as many as 1 out of 4 people with a broken hip.
What About Osteoporosis in Men?
Osteoporosis is not just a woman's disease. Men have it also, although not as often as women do. This is probably because most men have more bone mass than women do. Also, they lose bone more slowly as they age because the amount of testosterone they have drops much more gradually. Women have a quick decrease in estrogen with menopause. Men have only ¼ as many hip fractures as women. However, men over the age of 75 are three times more likely to die after a hip fracture than are women.
The disease has not been as well studied in men as in women. So, some prevention and treatment recommendations come from studies in women. The risk factors for men are similar to those for women—smoking, not enough calcium or vitamin D, too much alcohol, family history, too little exercise, and taking certain drugs. Low levels of testosterone in older men seem to increase their loss of bone and chance of hip fracture.
Older men who fracture a bone easily, who show bone loss on a normal x-ray, or have risk factors should get a DEXA-scan. If the scan shows osteoporosis, treatment, with the exception of estrogen and raloxifene, is similar to that suggested for older women. This includes getting enough calcium and vitamin D, doing weight-bearing exercise, not smoking, and limiting alcohol. The only drugs available for men are alendronate, risedronate, and calcitonin. Some men with low levels of testosterone may find testosterone supplements helpful.
The National Osteoporosis Foundation operates an information center on osteoporosis under a grant from the National Institute of Arthritis and Musculoskeletal and Skin Diseases with support from other parts of the National Institutes of Health and the Public Health Service. Contact them at:
NIH Osteoporosis and Related Bone Diseases
National Resource Center
1232 22nd Street, NW
Washington, DC 20037
Information provided by:
The National Institute on Aging (NIA) has a book and video about exercise for older people. For more information and a free publications list, write or call:
NIA Information Center
PO Box 8057
Gaithersburg, MD 20898-8057