Osteoporosis - overview

Definition

Osteoporosis is a disease in which bones become fragile and more likely to fracture. Usually the bone loses density, which measures the amount of calcium and minerals in the bone.

Alternative Names

Thin bones; Low bone density

Causes, incidence, and risk factors

Osteoporosis is the most common type of bone disease.

About half of all women over the age of 50 will have a fracture of the hip, wrist, or vertebra (bone of the spine) during their lifetime.

Bone is living tissue. Existing bone is constantly being replaced by new bone. Osteoporosis occurs when the body fails to form enough new bone, when too much existing bone is reabsorbed by the body, or both.

Calcium is one of the important minerals needed for bones to form. If you do not get enough calcium and vitamin D, or your body does not absorb enough calcium from your diet, your bones may become brittle and more likely to fracture.

Sometimes bone loss occurs without any cause. White women are more likely to have bone loss. Sometimes the tendency to have bone loss and thin bones is passed down through families.

Osteoporosis

A drop in estrogen in women at the time of menopause and a drop in testosterone in men is a leading cause of bone loss. Other causes of bone loss include:

  • Being confined to a bed
  • Certain medical conditions
  • Taking certain medications

Other risk factors include:

  • Absence of menstrual periods (amenorrhea) for long periods of time
  • A family history of osteoporosis
  • Drinking a large amount of alcohol
  • Low body weight
  • Smoking

Symptoms

There are no symptoms in the early stages of osteoporosis. Many times, people will have a fracture before learning that they have the disease.

Pain almost anywhere in the spine can be caused by fractures of the bones of the spine. These are called compression fractures. They often occur without an injury. The pain may occur suddenly or slowly over time.

There may be a loss of height (as much as 6 inches) over time. A stooped posture or kyphosis (also called a "dowager's hump") may develop.

Signs and tests

Bone mineral density testing (most often with a DEXA scan) measures your bone mineral density. Your health care provider uses this test to:

  • Diagnose bone loss and osteoporosis
  • Predict your risk of future bone fractures
  • See how well osteoporosis medicine is working

spine or hip x-ray may show fracture or collapse of the spinal bones. However, simple x-rays of other bones are not very accurate in predicting whether you are likely to have osteoporosis.

You may need other blood and urine tests if your osteoporosis is thought to be due to a medical condition, rather than simply the usual bone loss seen with older age.

Treatment

Treatment for osteoporosis may involve:

  • Lifestyle changes, such as diet and exercise
  • Taking calcium and vitamin D
  • Using medications

Medications are used to strengthen bones when:

  • Osteoporosis has been diagnosed by a bone density study, whether or not you have a fracture.
  • A bone fracture has occurred and a bone density test shows that you have thin bones, but not osteoporosis.

Medicines used to treat osteoporosis include:

  • Bisphosphonates (the main drugs used to prevent and treat osteoporosis in postmenopausal women)
  • Estrogens, teriparatide, raloxifene, and calcitonin

Exercise plays a key role in preserving bone density in older adults. Some of the exercises recommended to reduce your chance of a fracture include:

  • Weight-bearing exercises -- walking, jogging, playing tennis, dancing
  • Free weights, weight machines, stretch bands
  • Balance exercises -- tai chi, yoga
  • Rowing machines

Avoid any exercise that presents a risk of falling, or high-impact exercises that may cause fractures in older adults.

Your body needs calcium and vitamin D to keep your bones strong. Vitamin D helps your body absorb calcium.

  • Adults under age 50 should have 1,000 mg of caclium and 400 - 800 IU of vitamin D daily.
  • Women ages 51 to 70 should have 1,200 mg of calcium and 400 - 800 IU of vitamin D a day; men ages 51 to 70 need 1,000 mg of calcium and 400 - 800 IU of vitamin D a day.
  • Adults over age 70 should get 1,200 mg of calcium and 800 IU of vitamin D daily. 
  • Your doctor may recommend a calcium supplement.
  • Follow a diet that provides the proper amount of calcium and vitamin D.

Stop unhealthy habits:

  • Quit smoking, if you smoke.
  • Limit your alcohol intake. Too much alcohol can damage your bones, and put you at risk for falling and breaking a bone.

It is critical to prevent falls. Avoid sedating medications and remove household hazards to reduce the risk of fractures. Make sure your vision is good. Other ways to prevent falling include:

  • Avoid walking alone on icy days
  • Leave lights on at night so you can see better when walking around your house
  • Remove slippery rugs from your house
  • Use bars in the bathtub, when needed
  • Wear well-fitting shoes

There are two surgeries used to treat severe, disabling pain from spinal fractures due to osteoporosis:

  • Kyphoplasty
  • Vertebroplasty

Expectations (prognosis)

Medications to treat osteoporosis can help prevent future fractures, but spine bones that have already collapsed cannot be reversed.

Some people with osteoporosis become disabled from weakened bones. Hip fractures are one of the main reasons people are admitted to nursing homes.

Prevention

Calcium is essential for building and maintaining healthy bone. Vitamin D is also needed because it helps your body absorb calcium. Following a healthy, well-balanced diet can help you get these and other important nutrients throughout life.

Other tips for prevention:

  • Avoid drinking excess alcohol
  • Don't smoke
  • Get regular exercise

A number of medications are approved for the prevention of osteoporosis.

Figures

Bone density scanOsteoporosisOsteoporosisHip fractureVitamin D sourceCalcium benefitCalcium sourceBone-building exerciseChanges in spine with age

References

Management of osteoporosis in postmenopausal women: 2010 position statement of The North American Menopause Society. Menopause. 2010 Jan-Feb;17(1):25-54.

Lewiecki EM. In the clinic. Osteoporosis. Ann Intern Med. 2011;155(1):ITC1-1-15;quiz ITC1-16.

Park-Wyllie LY, Mamdani MM, Juurlink DN, Hawker GA, Gunraj N, Austin PC, et al. Bisphosphonate use and the risk of subtrochanteric or femoral shaft fractures in older women. JAMA. 2011;305(8):783-789.

National Osteoporosis Foundation. Clinician's Guide to Prevention and Treatment of Osteoporosis. Washington, DC: National Osteoporosis Foundation; 2010.

Revision

Last reviewed 6/16/2012 by David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.

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