Osteoporosis Overview

Osteoporosis, or porous bone, is a disease characterized by low bone mass and structural deterioration of bone tissue, leading to bone fragility and an increased susceptibility to fractures of the hip, spine, and wrist. Men as well as women suffer from osteoporosis, a disease that can be prevented and treated.

Facts and Figures

• Osteoporosis is a major public health threat for 44 million Americans, 68% of whom are women. 
• In the U.S. today, 10 million individuals already have osteoporosis and 34 million more have low bone mass, placing them at increased risk for this disease. 
• One out of every two women and one in four men over 50 will have an osteoporosis-related fracture in their lifetime. 
• More than 2 million American men suffer from osteoporosis, and millions more are at risk. Each year, 80,000 men suffer a hip fracture and one-third of these men die within a year. 
• Osteoporosis can strike at any age. 
• Osteoporosis is responsible for more than 1.5 million fractures annually, including 300,000 hip fractures, and approximately 700,000 vertebral fractures, 250,000 wrist fractures, and more than 300,000 fractures at other sites. 
• Estimated national direct expenditures (hospitals and nursing homes) for osteoporosis and related fractures is $14 billion each year.

What is Bone?

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 makes bone strong yet flexible to withstand stress. More than 99% of the body's calcium is contained in the bones and teeth. The remaining 1% is found in the blood. 

Throughout your lifetime, old bone is removed (resorption) and new bone is added to the skeleton (formation). During childhood and teenage years, new bone is added faster than old bone is removed. As a result, bones become larger, heavier, and denser. Bone formationcontinues at a pace faster than resorption until peak bone mass (maximum bone density and strength) is reached around age 30. After age 30, bone resorption slowly begins to exceed bone formation. Bone loss is most rapid in the first few years after menopause but persists into the postmenopausal years. Osteoporosis develops when bone resorption occurs too quickly or if replacement occurs too slowly. Osteoporosis is more likely to develop if you did not reach optimal bone mass during your bone building years. 

Risk Factors

Certain factors are linked to the development of osteoporosis or contribute to an individual's likelihood of developing the disease. These are called "risk factors." Many people with osteoporosis have several of these risk factors, but others who develop osteoporosis have no identified risk factors. There are some risk factors that you cannot change, and others that you can: 
Risk factors you cannot change: 

• Gender - Your chances of developing osteoporosis are greater if you are a woman. Women have less bone tissue and lose bone more rapidly than men because of the changes involved in menopause. 
• Age - the older you are, the greater your risk of osteoporosis. Your bones become less dense and weaker as you age. 
• Body size - Small, thin-boned women are at greater risk. 
• Ethnicity - Caucasian and Asian women are at highest risk. African-American and Latino women have a lower but significant risk.
• Family history - Susceptibility to fracture may be, in part, hereditary. People whose parents have a history of fractures also seem to have reduced bone mass and may be at risk for fractures.

Risk factors you can change:  

• Sex hormones: abnormal absence of menstrual periods (amenorrhea), low estrogen level (menopause), and low testosterone level in men. 
• Anorexia. 
• A lifetime diet low in calcium and vitamin D. 
• Use of certain medications, such as glucocorticoids or some anticonvulsants. 
• An inactive lifestyle or extended bed rest.
• Cigarette smoking. 
• Excessive use of alcohol.

Prevention

To reach optimal peak bone mass and continue building new bone tissue as you get older, there are several factors you should consider: 
Calcium. An inadequate supply of calcium over the lifetime is thought to play a significant role in contributing to the development of osteoporosis. Many published studies show that low calcium intakes appear to be associated with low bone mass, rapid bone loss, and high fracture rates. National nutrition surveys have shown that many people consume less than half the amount of calcium recommended to build and maintain healthy bones. Good sources of calcium include low fat dairy products, such as milk, yogurt, cheese and ice cream; dark green, leafy vegetables, such as broccoli, collard greens, bok choy and spinach; sardines and salmon with bones; tofu; almonds; and foods fortified with calcium, such as orange juice, cereals and breads. Depending upon how much calcium you get each day from food, you may need to take a calcium supplement.

Calcium needs change during one's lifetime. The body's demand for calcium is greater during childhood and adolescence, when the skeleton is growing rapidly, and during pregnancy and breastfeeding. Postmenopausal women and older men also need to consume more calcium. This may be caused by inadequate amounts of vitamin D, which is necessary for intestinal absorption of calcium. Also, as you age, your body becomes less efficient at absorbing calcium and other nutrients. Older adults also are more likely to have chronic medical problems and to use medications that may impair calcium absorption. 
 
 
Recommended Calcium Intakes *
Ages mg/day
Birth-6 months 210
6 months-1 year 270
1-3 500
4-8 800
9-13 1300
14-18 1300
19-30 1000
31-50 1000
51-70 1200
70 or older 1200
Pregnant or lactating 
14 - 18 1300
19 - 50 1000

* National Academy of Sciences (1997)

Vitamin D

Vitamin D plays an important role in calcium absorption and in bone health. It is synthesized in the skin through exposure to sunlight. While many people are able to obtain enough vitamin D naturally, studies show that vitamin D production decreases in the elderly, in people who are housebound, and during the winter. These individuals may require vitamin D supplementation to ensure a daily intake of between 400 to 800 IU of vitamin D. Massive doses are not recommended. 

Exercise

Like muscle, bone is living tissue that responds to exercise by becoming stronger. The best exercise for your bones is weight-bearing exercise, that forces you to work against gravity. These exercises include walking, hiking, jogging, stair-climbing, weight training, tennis, and dancing. 
Smoking. Smoking is bad for your bones as well as for your heart and lungs. Women who smoke have lower levels of estrogen compared to nonsmokers and frequently go through menopause earlier. Postmenopausal women who smoke may require higher doses of hormone replacement therapy and may have more side effects. Smokers also may absorb less calcium from their diets. 

Alcohol

Regular consumption of 2 to 3 ounces a day of alcohol may be damaging to the skeleton, even in young women and men. Those who drink heavily are more prone to bone loss and fractures, both because of poor nutrition as well as increased risk of falling. 

Medications that cause bone loss

The long-term use of glucocorticoids (medications prescribed for a wide range of diseases, including arthritis, asthma, Crohn's disease, lupus, and other diseases of the lungs, kidneys, and liver) can lead to a loss of bone density and fractures. Other forms of drug therapy that can cause bone loss include long-term treatment with certain antiseizure drugs, such as phenytoin (Dilantin®) and barbiturates; gonadotropin releasing hormone (GnRH) analogs used to treat endometriosis; excessive use of aluminum-containing antacids; certain cancer treatments; and excessive thyroid hormone. It is important to discuss the use of these drugs with your physician, and not to stop or alter your medication dose on your own. 

Prevention Medications

Various medications are available for the prevention, as well astreatment, of osteoporosis. See section entitled "Therapeutic Medications." 

Symptoms

Osteoporosis is often called the "silent disease" because bone loss occurs without symptoms. People may not know that they have osteoporosis until their bones become so weak that a sudden strain, bump, or fall causes a hip fracture or a vertebra to collapse. Collapsed vertebra may initially be felt or seen in the form of severe back pain, loss of height, or spinal deformities such as kyphosis, or severely stooped posture. 

Detection

Following a comprehensive medical assessment, your doctor may recommend that you have your bone mass measured. Bone mineral density (BMD) tests measure bone density in the spine, wrist, and/or hip (the most common sites of fractures due to osteoporosis), while others measure bone in the heel or hand. These tests are painless, noninvasive, and safe. Bone density tests can: 
 
 
Detect low bone density before a fracture occurs.
 
Confirm a diagnosis of osteoporosis if you have already fractured.
 
Predict your chances of fracturing in the future.
 
Determine your rate of bone loss and/or monitor the effects of treatment if the test is conducted at intervals of a year or more.

Treatment

A comprehensive osteoporosis treatment program includes a focus on proper nutrition, exercise, and safety issues to prevent falls that may result in fractures. In addition, your physician may prescribe a medication 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 a balanced proportion. In particular, calcium and vitamin D are needed for strong bones as well as for your heart, muscles, and nerves to function properly. (See Prevention section for recommended amounts of calcium.) 

Exercise

Exercise is an important component of an osteoporosis prevention and treatment program. Exercise not only improves your bone health, but it 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. Asextra insurance against fractures, your doctor can recommend specific exercises to strengthen and support your back. 

Therapeutic Medications

Currently, alendronate, raloxifene and risedronate are approved by the U. S. Food and Drug Administration (FDA) for the prevention and treatment of postmenopausal osteoporosis. Teriparatide is approved for the treatment of the disease in postmenopausal women and men who are at high risk for fracture. Estrogen/hormone therapy (ET/HT) is approved for the prevention of postmenopausal osteoporosis, and calcitonin is approved for treatment. In addition, alendronate is approved for the treatment of osteoporosis in men, and both alendronate and risedronate are approved for use by men and women with glucocorticoid-induced osteoporosis.

Alendronate

Alendronate (brand name Fosamax®) is a medication from the class of drugs called bisphosphonates. Like estrogen and raloxifene, alendronate is approved for both the prevention and treatment of osteoporosis. Alendronate is also used to treat the bone loss from glucocorticoid medications like prednisone or cortisone and is approved for the treatment of osteoporosis in men. In postmenopausal women with osteoporosis, the bisphosphonate alendronate reduces bone loss, increases bone density in both the spine and hip, and reduces the risk of both spine fractures and hip fractures. Side effects from alendronate are uncommon, but may include abdominal or musculoskeletal pain, nausea, heartburn, or irritation of the esophagus. The medication should be taken on an empty stomach and with a full glass of water first thing in the morning. After taking alendronate, it is important to wait in an upright position for at least one-half hour, or preferably one hour, before the first food, beverage, or medication of the day. 

Risedronate

Risedronate sodium (brand name Actonel®) is approved for the prevention and treatment of osteoporosis in postmenopausal women and for the prevention and treatment of glucocorticoid-induced osteoporosis in both men and women.  Risedronate, a bisphosphonate, has been shown to slow or stop bone loss, increase bone mineral density and reduce the risk of spine and non-spine fractures.  In clinical trials, side effects of risedronate were minimal to moderate and those that were reported occurred equally among people taking the medication and those taking a placebo.  Risedronate should be taken with a glass of water at least 30 minutes before the first food or beverage of the day other than water.  After taking risedronate, it is important to remain in an upright position and refrain from eating for at least 30 minutes.

Raloxifene

Raloxifene (brand name Evista®) is a drug that is approved for the prevention and treatment of postmenopausal osteoporosis. It is from a new class of drugs called Selective Estrogen Receptor Modulators (SERMs) that appear to prevent bone loss at the spine, hip, and total body. Raloxifene has been shown to have beneficial effects on bone mass and bone turnover and can reduce the incidence of vertebral fractures. While side-effects are not common with raloxifene, those reported include hot flashes and deep vein thrombosis, the latter of which is also associated with estrogen therapy. Additional research studies on raloxifene will be ongoing for several more years.

Calcitonin

Calcitonin is a naturally occurring non-sex hormone involved in calcium regulation and bone metabolism. In women who are at least 5 years beyond menopause, calcitonin slows bone loss, increases spinal bone density, and according to anecdotal reports, relieves the pain associated with bone fractures. Calcitonin reduces the risk of spinal fractures and may reduce hip fracture risk as well. Studies on fracture reduction are ongoing. Calcitonin is currently available as an injection or nasal spray. While it does not affect other organs or systems in the body, injectable calcitonin may cause an allergic reaction and unpleasant side effects including flushing of the face and hands, urinary frequency, nausea, and skin rash. The only side effect reported with nasal calcitonin is a runny nose. 

Teriparatide

Teriparatide (brand name Forteo®) is an injectable form of human parathyroid hormone that is approved for postmenopausal women and men with osteoporosis who are at high risk for having a fracture. Teriparatide stimulates new bone formation in both the spine and hip and reduces the risk of vertebral and non-vertebral fractures in postmenopausal women. In men, teriparatide reduces the risk of vertebral fractures but the study was not large enough to examine the effect on nonvertebral fractures. Side effects include nausea, dizziness and leg cramps. Teriparatide is approved for use for up to 24 months.

Estrogen/Hormone Therapy

Estrogen/hormone therapy (ET/HT) has been shown to reduce bone loss, increase bone density in both the spine and hip, and reduce the risk of hip and spine fractures in postmenopausal women. ET/HT is approved for the prevention of postmenopausal osteoporosis and is most commonly administered in the form of a pill or skin patch. When estrogen (estrogen therapy or ET) is taken alone, it can increase a woman’s risk of developing cancer of the uterine lining (endometrial cancer). To eliminate this risk, physicians prescribe the hormone progestin in combination with estrogen (hormone therapy/HT) for those women who have not had a hysterectomy. Side effects of ET/HT include vaginal bleeding, breast tenderness, mood disturbances, venous blood clots and gallbladder disease.

The Women’s Health Initiative (WHI), a large government-funded research study, recently demonstrated that HT (Prempro®) is associated with a modest increase in the risk of breast cancer, stroke, and heart attack. The WHI also demonstrated that ET is associated with an increase in the risk of stroke. Another large study from the National Cancer Institute (NCI) indicated that long-term use of ET may be associated with an increase in the risk of ovarian cancer. It is not yet clear whether HT carries a similar risk.
Any estrogen therapy should be prescribed for the shortest period of time possible. When used solely for the prevention of postmenopausal osteoporosis, any ET/HT regimen should only be considered for women at significant risk of osteoporosis and non-estrogen medications should be carefully considered.

Fall Prevention

Fall Prevention is a special concern for men and women with osteoporosis. Falls can increase the likelihood of fracturing a bone in the hip, wrist, spine or other part of the skeleton. In addition to the environmental factors listed below, falls can also be caused by impaired vision and/or balance, chronic diseases that impair mental or physical functioning, and certain medications, such as sedatives and antidepressants. It is important that individuals with osteoporosis be aware of any physical changes they may be experiencing that affect their balance or gait, and that they discuss these changes with their health care provider. 

Some tips to help eliminate the environmental factors that lead to falls include: 

Outdoors

Use a cane or walker for added stability; wear rubber-soled shoes for traction; walk on grass when sidewalks are slippery; in winter, carry salt or kitty litter to sprinkle on slippery sidewalks; be careful on highly polished floors that become slick and dangerous when wet. Use plastic or carpet runners when possible.

Indoors

Keep rooms free of clutter, especially on floors; keep floor surfaces smooth but not slippery; wear supportive, low-healed shoes even at home; avoid walking in socks, stockings, or slippers; be sure carpets and area rugs have skid-proof backing or are tacked to the floor; be sure stairwells are well lit and that stairs have handrails on both sides; install grab bars on bathroom walls near tub, shower, and toilet; use a rubber bath mat in shower or tub; keep a flashlight with fresh batteries beside your bed; if using a step stool for hard to reach areas, use a sturdy one with a handrail and wide steps; add ceiling fixtures to rooms lit by lamps. Consider purchasing a cordless phone so that you don't have to rush to answer the phone when it rings or you can call for help if you do fall. 

Revision Date: 1/2003

The NIH Osteoporosis and Related Bone Diseases ~ National Resource Center is supported by the
National Institute of Arthritis and Musculoskeletal and Skin Diseases
with contributions from the National Institute of Child Health and Human Development, National Institute of
Dental and Craniofacial Research, National Institute of Diabetes and Digestive and Kidney Diseases,
NIH Office of Research on Women's Health, DHHS Office on Women's Health, and National Institute on Aging.