What Is Osteoporosis?
Bone is made up of calcium and protein. There are two types of bone — compact bone and spongy bone. Each bone in the body contains some of each type. The first signs of osteoporosis are seen in bones that have a lot of spongy bone, such as the spine, hip and wrist.

Once made, bone is always changing. Old bone is removed in a process called resorption, and new bone is formed in a process called formation. From childhood until age 30 years, bone is formed faster than it is broken down. After age 30 years, the process begins to reverse: bone is broken down faster than it is made. Too much bone loss can result in osteoporosis.

With osteoporosis, bones become thin and brittle because more bone is lost than formed.

Osteoporosis can pose a special threat to women. Estrogen — a female hormone — protects against bone loss. As a woman nears menopause, her body produces less estrogen.

Some symptoms of osteoporosis are back pain or tenderness. Signs include a loss of height, and a slight curving of the upper back.

Osteoporosis affects at least 10 million Americans — most of whom are women. Each year, more than 1.5 million fractures related to osteoporosis occur in the United States. As many as 24 percent of patients older than 50 years with a hip fracture die in the year following their fracture from problems caused by lack of activity, such as blood clots and pneumonia.

Risk Factors
Compared with men, women are more at risk of osteoporosis because their bones are smaller and lighter than men's.

Prevention
It is hard to grow new bone after it is lost, so prevention is important. To prevent osteoporosis, focus on building and keeping as much bone as you can.

Exercise
Exercise increases bone mass before menopause and slows bone loss after menopause. Active women have higher bone density than women who do not exercise.

Diet
Bone loss can increase if your diet is low in calcium. Calcium slows the rate of bone loss.

Good sources of calcium are dairy products, such as milk and yogurt. Other sources are leafy green vegetables, nuts, seafood, and juices and cereals that are fortified with calcium. A well-balanced diet is very healthy for bones.

Detection
You should have a physical exam once a year. During this exam, you can be given special tests that show the density of bone.

Bone mineral density tests measure bone mass in the heel, spine, hip, hand or wrist. Measuring one area can give your doctor a sense of your bone density in other parts of your skeleton.

Dual-Energy X-ray Absorptiometry
Dual-energy X-ray absorptiometry (DXA) is used most often to measure the bone density of your spine or hip. It is currently the most accurate test available.

Quantitative Computed Tomography
Quantitative computed tomography (QCT) uses both computed tomography scanning and computer software to test the bone density of the spine.

Quantitative Ultrasonography
This test, which often takes less than one minute, uses sound waves instead of radiation to measure bone density.

Treatment
There are many treatment options available to help reduce the risk of fracture.

Hormone Therapy
Hormone therapy slows bone loss after menopause. Estrogen has been shown to decrease the risk of hip fractures and spinal deformities. Estrogen also can relieve symptoms that occur around menopause, such as hot flushes (hot flashes).

Selective Estrogen Receptor Modulators
Women also can take a type of drug known as selective estrogen receptor modulators (SERMs) to help prevent some of the bone problems that can occur during menopause.

SERMs may be a good choice for women who need protection from osteoporosis, but can't or don't want to take HT.

Bisphosphonates
If a woman does not take estrogen or SERMs, there is another option for preventing osteoporosis — bisphosphonates. These medications are used to slow bone breakdown.

Other Options
Another medication used to slow the breaking down of bone is called calcitonin. It can be given by injection or nasal spray.

Finally ...
To increase your chances of staying healthy, you have an important goal — to prevent bone loss. Exercise every day, even if you walk only a few blocks, and get enough calcium.

This excerpt from ACOG's Patient Education Pamphlet is provided for your information. It is not medical advice and should not be relied upon as a substitute for visiting your doctor. If you need medical care, have any questions, or wish to receive the full text of this Patient Education Pamphlet, please contact your obstetrician-gynecologist.