Osteoporosis

Osteoporosis, which means "porous bone," is a disease characterized by low bone mass (bone thinning) that leads to fragile bones and an increased risk of fractures of the hip, spine, and wrist. Men as well as women are affected by this condition. Osteoporosis is a disease that can be prevented and treated.

Understanding Osteoporosis and Bones

Bone is living, growing tissue. It is made mostly of collagen, a protein that provides a soft framework, and calcium phosphate, a mineral that adds strength and hardens the framework.

This combination of collagen and calcium phosphate makes bone both flexible and strong, which, in turn, helps it withstand stress. More than 99 percent of the body's calcium is contained in the bones and teeth. The remaining 1 percent is found in the blood.

Throughout your lifetime, old bone is removed (a process called resorption) and new bone is added to the skeleton (a process called formation). During childhood and the teenage years, new bone is added faster than old bone is removed. As a result, bones become larger, heavier, and denser. Bone formation outpaces resorption until peak bone mass (maximum bone density and strength) is reached around age 30. After that time, bone resorption slowly begins to exceed bone formation.

There are two main types of osteoporosis: primary and secondary.

Primary

In cases of primary osteoporosis, either the condition is caused by age-related bone loss (sometimes called senile osteoporosis), or the cause may be unknown (called idiopathic osteoporosis). The term idiopathic osteoporosis is used only for people who are under the age of 70; in older people, age-related bone loss is assumed to be the cause.

Secondary

In cases of secondary osteoporosis, the loss of bone mass is caused by certain lifestyle factors, diseases, or medications. The majority of people with osteoporosis have at least one secondary cause.

Risk Factors You Cannot Change

There are a number of risk factors for osteoporosis that you cannot change, including:

• Gender. Your chances of developing osteoporosis are greater if you are a woman. Women have less bone tissue and lose bone faster than men because of the changes that happen with menopause.
• Age. The older you are, the greater your risk of osteoporosis. Your bones become thinner and weaker as you age.
• Body size. Small, thin-boned women are at greater risk for developing osteoporosis than larger women.
• Ethnicity. Caucasian and Asian women are at the highest risk of developing the disease. African-American and Hispanic women have a lower, but still significant, risk.
• Family history. Your risk for fractures may be due, in part, to heredity. People whose parents have a history of fractures also seem to have reduced bone mass and may be at risk for fractures themselves.

Risk Factors You Can Change

The good news is that there are a number of risk factors for osteoporosis you can change, including:

• Sex hormones. Abnormal absence of menstrual periods (amenorrhea), low estrogen levels (menopause), and low testosterone levels in men can bring on osteoporosis.
• Anorexia nervosa. Characterized by an irrational fear of weight gain, this eating disorder increases your risk for osteoporosis.
• Calcium and vitamin D intake. A lifetime diet low in calcium and vitamin D makes you more prone to bone loss.
• Medication use. Long-term use of glucocorticoids and some anticonvulsants can lead to loss of bone density, which can ultimately result in fractures.
• Lifestyle. An inactive lifestyle or extended bed rest tends to weaken bones.
• Cigarette smoking. Cigarettes are bad for the bones as well as the heart and lungs.
• Alcohol intake. Excessive consumption of alcohol increases the risk of bone loss and fractures.

Signs and Symptoms of Osteoporosis

People with osteoporosis often don't know they have it, simply because there are no osteoporosis symptoms in the early stages of the disease. That is what led specialists to label osteoporosis as the "silent disease."

As osteoporosis progresses, you may develop symptoms related to weakened bones, including:

• Back pain
• Loss of height and stooped posture
• A curved backbone (known as a dowager's hump)
• Fractures that may occur with a minor injury, especially of the hip, spine, or wrist.

Making a Diagnosis Before Symptoms Develop

Specialized tests called bone density tests can measure bone density in various sites of the body, thereby predicting those who are at greater risk of developing symptoms of osteoporosis. A bone density test can:

• Detect osteoporosis before a fracture occurs
• Predict your chances of fracturing in the future
• Determine the rate of bone loss
• Monitor the effects of treatment if the test is conducted at intervals of a year or more.

The most common bone mineral density test is dual-energy x-ray absorptiometry (DEXA). The results of the DEXA test are scored in comparison to the bone mineral density (BMD) of young, healthy individuals, resulting in a measurement called a T-score. If your T-score is -2.5 or lower, you are considered to have osteoporosis and, therefore, are at high risk for a fracture. T-scores between -1.0 and -2.5 are generally considered to show osteopenia (a reduction in bone mass that is not as severe as with osteoporosis). The risk of fractures is generally lower in people with osteopenia when compared to those with osteoporosis. However, if bone loss continues in a person with osteopenia, the risk for fracture increases, too.

The United States Preventive Services Task Force recommends that all women age 65 or older routinely have a bone mineral density test to screen for osteoporosis. If you have a higher risk for fractures, routine screening should begin at age 60.

Osteoporosis Treatment

A comprehensive treatment program for osteoporosis deals with:

• Proper nutrition
• Exercise
• Safety issues to prevent falls that may result in fractures.

In addition, your physician may prescribe medication as part of your osteoporosis treatment to slow or stop bone loss, increase bone density, and reduce fracture risk.

Nutrition

The foods we eat contain a variety of vitamins, minerals, and other important nutrients that help keep our bodies healthy. All of these nutrients are needed in balanced proportion. In particular,calcium and vitamin D are needed for strong bones and for your heart, muscles, and nerves to function properly.

Exercise

Exercise is an important component of an osteoporosis prevention and treatment program. Exercise not only improves your bone health, but it also increases muscle strength, coordination, and balance, and leads to better overall health. While exercise is good for someone with osteoporosis, it should not put any sudden or excessive strain on your bones. As extra insurance against fractures, your doctor can recommend specific exercises to strengthen and support your back.

Medications

There are a number of medications currently approved for treating osteoporosis, including:

• Alendronate (Fosamax^®)
• Risedronate (Actonel^®)
• Ibandronate (Boniva^®)
• Calcitonin (Miacalcin^®, Fortical^®)
• Raloxifene (Evista^®)
• Estrogen therapy (ET) or hormone therapy (HT)
• Parathyroid hormone or teriparatide (Forteo^®).

Alendronate (Fosamax)

This drug belongs to a class of drugs called bisphosphonates and is approved for both osteoporosis prevention and treatment. It is used to treat bone loss from the long-term use of osteoporosis-causing medications and is also used for osteoporosis in men. In postmenopausal women, it has shown to be effective at reducing bone loss, increasing bone density in the spine and hip, and reducing the risk of spine and hip fractures.

Risedronate (Actonel)

Like alendronate, risedronate is also a bisphosphonate. It is approved for:

• Osteoporosis prevention and treatment
• Bone loss from the long-term use of osteoporosis-causing medications
• Osteoporosis in men.

Risedronate has been shown to slow bone loss, increase bone density, and reduce the risk of spine and non-spine fractures.

Ibandronate (Boniva)

Ibandronate is approved for the prevention and treatment of postmenopausal osteoporosis. Taken as a once-a-month pill, ibandronate should be taken on the same day each month. Ibandronate reduces bone loss, increases bone density, and reduces the risk of spine fractures.

Calcitonin (Miacalcin, Fortical)

Calcitonin is a naturally occurring hormone involved in calcium regulation and bone metabolism. Calcitonin can be injected or taken as a nasal spray. In women who are at least five years beyond menopause, it slows bone loss and increases spinal bone density. Women report that it also eases pain associated with bone fractures.

Raloxifene (Evista)

This drug is a selective estrogen receptor modulator (SERM) that has many estrogen-like properties. It is approved for osteoporosis treatment and prevention, and can prevent bone loss at the spine, hip, and other areas of the body. Studies have shown that it can decrease the rate of vertebral fractures by 30 percent to 50 percent.

Estrogen Therapy (ET) or Hormone Therapy (HT)

These drugs, which have been used to treat the symptoms of menopause, also are used to prevent bone loss. However, recent studies suggest that this might not be a good option for many women. The U.S. Food and Drug Administration (FDA) has made the following recommendations for taking ET and HT:

• Take the lowest possible doses of ET or HT for the shortest period of time to manage symptoms of menopause
• Talk with your doctor about using other osteoporosis medications instead.

Parathyroid Hormone or Teriparatide (Forteo)

Forteo is approved for treating osteoporosis in postmenopausal women and for men who are at high risk for a fracture. It helps new bone to form and increases bone density. In postmenopausal women, it has been shown to reduce fractures in the spine, hip, foot, ribs, and wrist. In men, it can reduce fractures in the spine. It can be taken as a daily injection for up to 24 months.

Osteoporosis Research

The field of research on osteoporosis has grown in recent years. This has resulted in significant advances in determining the causes of osteoporosis, assessing risk factors, and creating new treatment methods. Several initiatives that are focused on skeletal biology should help in developing strategies to maintain and enhance bone density in childhood.