Your are here: Home > Women's Health Center > Boning up on osteoporosis

Boning up on osteoporosis

Due to an increase in media attention during the last few years, osteoporosis has become a household word. But despite the abundance of available information, contradictions and confusion abound.

Much of the existing information on osteoporosis consists of brief reports about new research results and does not explain the complexity of the issues or the risks involved in prevention and treatment options. Increasing use of the media by manufacturers to advertise hormones and other prescription medications, nonprescription medications, and calcium-rich food products, is promoting the spread of biased information.

This article provides some basic information about osteoporosis, including what it is, who is at risk, and how to prevent it. Areas of confusion and disagreement are noted, and resources are suggested for further information.

What is osteoporosis?

Osteoporosis is a disease of the bones characterized by low bone mass (density) and increased fragility of the remaining bone. Bones are made up of living tissue that is constantly being renewed. This process, called remodeling, consists of two stages-- resorption and formation. During resorption, old bone is broken down and removed. During bone formation, new bone is built to replace the old.

The remodeling process changes naturally throughout the life cycle. During childhood and early adulthood, new bone is formed faster than old bone is removed. Between ages 25 and 35, a peak bone mass (maximum density and strength) is reached. After age 35, bone loss outpaces bone formation. In women, the rate of loss is greatest during the first four to five years after menopause.

Osteoporosis occurs when there is an excessive amount of bone loss and/or insufficient bone formation. The bones become thin and weak, increasing the chance of fractures. Fractures are most common in the hip, spine, wrist, and ribs, but can occur in any bone. These fractures can cause severe pain, loss of height, or spinal deformities, such as stooped posture or dowager's hump.

Because bone loss occurs without symptoms, people may not realize they have osteoporosis until a sudden bump or fall causes a fracture. Bone density tests are available, but some studies have shown that low bone density alone does not always indicate osteoporosis or an increase in fractures. In addition, there are variations in how the results are interpreted, and the most accurate tests are quite costly.

Who is at risk?

In the United States, 7 to 8 million people have osteoporosis, and another 17 million have bone mass low enough to increase their risk for the disease. The major risk factors fall into several categories--biological, lifestyle, and medical--as shown in the following chart. However, these are only general indicators of risk.

For example, although osteoporosis occurs most often in older people, it can develop at any age. Women are four times more likely than men to develop it because they usually have smaller, thinner bones and lose bone rapidly after menopause. But men also develop osteoporosis, especially after age 65. Whites and Asians are at higher risk, but Blacks and Hispanics can also get the disease.

The rate of bone loss and development of osteoporosis are affected by many interrelated factors that vary with the individual. Among them are the amount of calcium in the diet and how well the body absorbs it, amount and type of physical activity, and hormonal balance. Although both the media and the medical community focus on the decrease in estrogen after menopause as the cause, it is only one of many factors.

Prevention at All Ages

Since osteoporosis occurs mainly in older people, why should you be concerned about it during earlier years? Prevention of osteoporosis can begin with lifestyle factors in childhood, when bone mass is increasing. Diet, exercise, smoking, and use of alcohol and caffeine all affect bone formation throughout life. Preventive measures become more important when bone mass is decreasing, especially during midlife and just after menopause in women.

Calcium

Good nutrition, especially an adequate supply of calcium, plays an important part in maintaining bone mass. Vitamin D and magnesium are also needed to aid calcium absorption.

Most people can get adequate amounts of calcium from food. Dairy products are the best dietary source of calcium. Other sources include sardines and salmon canned with bones, broccoli, dark green leafy vegetables such as spinach, and tofu processed with calcium salts. See the Recommended calcium ntakes chart below to determine how much calcium you need.

If you cannot get enough calcium from your diet, you may need to take a calcium supplement. However, supplements should be used only to supplement the calcium in your diet, not replace it. There are several different calcium compounds on the market. They differ mainly in price and how easily they are absorbed. Be sure to discuss calcium supplementation with your physician.

Exercise

Exercise is an important contributor to building and maintaining bone mass at all ages. It also increases the strength and coordination of muscles that support the bones. Weight-bearing exercise, such as walking, jogging, stair climbing, jumping rope, and dancing, is the best for your bones.

Other lifestyle factors

Smoking, alcohol, and caffeine can contribute to bone loss. To reduce your risk, do not smoke, and limit your use of alcohol and caffeine.

The Hormone Controversy

Substantial controversy exists, even among physicians, regarding the use of hormones and other medications to slow bone loss in midlife and older years. The disagreement centers around two issues: 1) the effectiveness of estrogen to slow bone loss and reduce risk of fractures (as well as to prevent heart disease) and 2) the increase in risk for breast and endometrial (uterine) cancer noted in women taking estrogen.

At one end of the spectrum are doctors who recommend that all postmenopausal women take estrogen. At the other are those who limit estrogen replacement to women who have had their ovaries removed or an early reduction or loss in production of ovarian hormones, especially estrogen.

While research studies have not provided a definitive argument for the use of estrogen, pharmaceutical companies are aggressively promoting its use. Women's health advocates, such as the National Women's Health Network, believe that hormone therapy may be useful in some high- risk cases. They advise women to carefully evaluate their risks for osteoporosis, heart disease, and breast and endometrial cancer and to consider other means of prevention before taking hormones.

Most parties agree, however, that each woman should talk with her health care provider about her individual risks and benefits. Women who do take estrogen and have not had a hysterectomy are generally advised to take hormone replacement therapy (HRT), which includes progesterone as well as estrogen, in order to reduce the risk of endometrial cancer.

Medications for Prevention and Treatment

Several medications have been approved by the U.S. Food and Drug Administration (FDA) for the prevention and treatment of osteoporosis. Calcitonin (Miacalcin), a naturally occuring hormone that slows bone loss, is available as an injection or nasal spray. Two drugs known as bisphosphonates—alendronate sodium (Fosamax) and risedronate sodium (Actonel)—are taken in pill form and help reduce bone loss, increase bone density in the spine and hip, and help reduce the risk of spine and hip fractures. Raloxifene (Evista), a drug in the class of Selective Estrogen Receptor Modulators, helps prevent bone loss at the spine, hip, and total body and may increase bone mass. It is available in pill form.

Determining Your Prevention Strategy

There is general agreement that everyone can reduce their risk of developing osteoporosis by making lifestyle changes. A healthy diet and regular exercise are important throughout life beginning in childhood.

Women from midlife on, older men, and anyone else at increased risk for osteoporosis should evaluate their risk factors in order to develop a prevention strategy appropriate for their individual needs. How you implement lifestyle changes and whether you take hormones or other medication are decisions that should be made by you and your health care provider. As you gather your information, examine it with a critical eye and be aware of vested interests and the credibility of sources.