Osteoporosis and Osteopenia

September 20, 2011

Osteoporosis, or porous bone, is a disease characterized by low bone mass and reduced bone strength, with increased risk of fractures. The term osteopenia means low bone mass, which is one aspect of osteoporosis. Osteopenia is often used to describe a mild form of osteoporosis because osteoporosis is diagnosed primarily by low bone density. Several diseases produce low bone density and osteoporosis is the most common of these.

Osteoporosis is often called the “silent disease.” It can go undetected until a fracture suddenly occurs. Any bone can be affected, but osteoporotic fractures most often involve the hip and spine. The wrist is also a common fracture site. Spinal (vertebral) fractures can be very painful or they can occur silently over many years, without pain, causing a gradual loss of height or a bent upper back (dowager’s hump).

RISK FACTORS

In general, older women are at greater risk of developing osteoporosis than men, because the decline in estrogen production at menopause speeds the loss of bone. Half of all women who live to 85 will have an osteoporosis-related fracture at some point. Although older women are at highest risk, osteoporosis can also develop in older men, and occasionally even in younger women and men. Risk factors for osteoporosis include: a personal history of fracture, family history of fracture in a first-degree (closely related) relative, a family history of osteoporosis, being female, lower body weight (weighing

DIAGNOSIS AND SCREENING

Regular x-rays are not accurate for measuring bone density. Osteoporosis is best diagnosed by measuring bone density at the hip, spine, and/or forearm using a special x-ray known as DEXA. Ultrasound (of the heel for instance) is sometimes used to diagnose osteoporosis, but is less accurate. When a patient’s bone mineral density (BMD) is measured, it is compared against the average bone density for a young healthy person of the same gender. DEXA results include the “T score,” which is the number of standard deviations above or below the bone density for young healthy people. Osteoporosis is diagnosed when the bone density is more than 2.5 standard deviations below this average (T score less than —2.5). Bone density between 1 and 2.5 standard deviations below the average (T score between —1 and —2.5) is called osteopenia.

Because osteoporosis develops silently, screening with DEXA is recommended for women age 65 and older, according to the U.S. Preventive Services Task Force (USPSTF). Between age 60 and 65, women at higher risk (body weight

PREVENTION

Bone mass peaks before age 30. Osteoporosis can be postponed by building up a healthy bone mass in childhood and young adulthood. By starting adult life with a higher bone mass, more time will pass before the bone mass becomes dangerously low. Bone mass can be maximized and maintained by including enough calcium in the diet, regular weight-bearing exercise, avoidance of smoking, and avoidance of more than moderate alcohol intake.

Calcium in the diet is very important. A daily total of 1,000 mg of calcium is recommended for most adults, but 1,500 mg is suggested for postmenopausal women. Teens, women in their early 20s, and breast-feeding women should get 1,200-1,500 mg per day. Foods high in calcium include milk, cheese, yogurt, sardines, broccoli, eggs, salmon, peanuts, soybeans, tofu, and spinach. One cup of 1% milk contains about 250 mg of calcium, one cup of broccoli has about 178 mg, and 1 cup of kidney beans has about 115 mg. Orange juice, soy milk, and other nondairy “milk” with added calcium are available. However, some women have difficulty obtaining enough calcium from foods alone, especially if they avoid dairy products.

Calcium supplements are recommended if the diet does not supply enough calcium. There are several kinds of calcium supplement (such as calcium carbonate or calcium citrate), some containing vitamin D as well.

When reading the label on calcium supplements, look for the amount of “elemental calcium.” The body will not absorb more than about 500 mg of elemental calcium at a time, so if more is needed, the doses should be spread out through the day. Postmenopausal women should consider taking vitamin D as well, especially in winter in the northern latitudes. Calcium can interfere with the absorption of some medications, and people with a history of kidney stones should check with their doctor before taking calcium supplements.

Weight-bearing exercise can help prevent the development of osteoporosis, and of course is beneficial for other health reasons. Weight-bearing exercise is activity that exerts a force or stress on bones, such as walking. Bone responds to even mild forces or pressure by becoming more dense. The key is to include moderate weight-bearing exercise in your daily routine. Vigorous exercise is not needed for maintenance of bone density, and can increase the risk of fracture in a person who has osteoporotic bones. Very vigorous exercise, as may be performed by an elite athlete, can actually cause a decrease in bone mass in young women by decreasing the body’s production of estrogen. For many older women, a daily walk with good supportive shoes or sneakers is effective. Walking provides good gentle stress to the bones in the spine and legs. For women who can safely exercise more vigorously, jogging and climbing stairs are good. Exercises to strengthen the muscles that hold the back erect are beneficial. These include exercises that gently arch the back. Resistance training is also helpful. This involves exercise against a resistance, by using an elastic exercise band (one brand name is Theraband), or walking in water (water exercises), or lifting weights. Your physician or physical therapist can help you design an exercise program that is appropriate for you.

Smoking and excessive alcohol intake are both known to increase the risk of osteoporosis, so efforts to stop smoking and limit alcohol intake are important.

TREATMENT

If you have osteoporosis, it is important to follow your physician’s recommendations. Your physician may consider laboratory tests to rule out various secondary causes of osteoporosis. Treatment of osteoporosis includes continuing the above preventive measures, and usually adding medications, with the goal of slowing the progression of the disease and reducing the chance of fractures. Currently there are several effective medications that have been approved by the Food and Drug Administration for the treatment (and prevention) of osteoporosis. These include hormones such as estrogen, raloxifene, and calcitonin, as well as bisphosphonate medications such as alendronate. Women who take calcium supplements regularly should also take vitamin D, to help the calcium be absorbed into the bones.

Once osteoporosis has developed, the risk of fractures can be reduced by minimizing the chance of falls. This may involve such measures as wearing sensible low shoes, using a cane or a walker if needed, avoiding clutter or throw rugs on the floor in the home, installing helpful wall rails in the bathroom, and avoiding medications that can cause grogginess or dizziness. Other precautionary antifall measures may be needed, depending upon your level of ability or disability.

SEE ALSO: Falls Prevention, Hormone replacement therapy, Menopause, Vitamins

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