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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 risk of fractures of the hip, spine, and wrist. Men as well as women are affected by osteoporosis, a disease that can be prevented and treated. In the United States, more than 40 million people either already have osteoporosis or are at high risk due to low bone mass.
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 both flexible and strong, which in turn helps bone to 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 one’s 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 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.
For women, bone loss is fastest in the first few years after menopause, and it continues into the postmenopausal years. Osteoporosis—which mainly affects women but may also affect men—will develop when bone resorption occurs too quickly or when replacement occurs too slowly. Osteoporosis is more likely to develop if you did not reach optimal peak bone mass during your bone-building years.
Certain risk factors are linked to the development of osteoporosis and contribute to an individual’s likelihood of developing the disease. Many people with osteoporosis have several risk factors, but others who develop the disease have no known risk factors. Some risk factors cannot be changed, but you can change others.
To reach optimal peak bone mass and continue building new bone tissue as you age, you should consider several factors.
Calcium: An inadequate supply of calcium over a lifetime contributes to the development of osteoporosis. Many published studies show that low calcium intake appears to be associated with low bone mass, rapid bone loss, and high fracture rates. National nutrition surveys show that many people consume less than half the amount of calcium recommended to build and maintain healthy bones. Food 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 on 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. 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.
|Source: Food and Nutrition Board, Institute of Medicine, National Academy of Sciences, 2010.|
|Infants 0 to 6 months||200|
|Infants 6 to 12 months||260|
|1 to 3 years old||700|
|4 to 8 years old||1,000|
|9 to 13 years old||1,300|
|14 to 18 years old||1,300|
|19 to 30 years old||1,000|
|31 to 50 years old||1,000|
|51- to 70-year-old males||1,000|
|51- to 70-year-old females||1,200|
|70 years old||1,200|
|14 to 18 years old, pregnant/lactating||1,300|
|19 to 50 years old, pregnant/lactating||1,000|
Vitamin D: Vitamin D plays an important role in calcium absorption and bone health. Food sources of vitamin D include egg yolks, saltwater fish, and liver. Many people obtain enough vitamin D naturally; however, studies show that vitamin D production decreases in the elderly, in people who are housebound, and for people in general during the winter. Adults should have vitamin D intakes of 600 IU (International Units) daily up to age 70. Men and women over age 70 should increase their uptake to 800 IU daily.
Exercise: Like muscle, bone is living tissue that responds to exercise by becoming stronger. Weight-bearing exercise is the best for your bones because it forces you to work against gravity. Examples include walking, hiking, jogging, climbing stairs, weight training, tennis, and dancing.
Smoking: Smoking is bad for your bones as well as your heart and lungs. Women who smoke have lower levels of estrogen compared with nonsmokers, and they often go through menopause earlier. 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 fracture, because of both poor nutrition and increased risk of falling.
Medications that cause bone loss: Several medications can contribute to bone loss. For example, 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 fracture. Bone loss also can result from long-term treatment with certain antiseizure drugs, such as phenytoin (Dilantin)1 and barbiturates; gonadotropin-releasing hormone (GnRH) drugs 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 doctor and not to stop or change your medication dose on your own.
1 Brand names included in this publication are provided as examples only, and their inclusion does not mean that these products are endorsed by the National Institutes of Health or any other Government agency. Also, if a particular brand name is not mentioned, this does not mean or imply that the product is unsatisfactory.
Osteoporosis is often called a 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 to fracture or a vertebra to collapse. Collapsed vertebrae may initially be felt or seen in the form of severe back pain, loss of height, or spinal deformities such as kyphosis (severely stooped posture).
Following a comprehensive medical assessment, your doctor may recommend that you have your bone mass measured. A bone mineral density (BMD) test is the best way to determine your bone health. BMD tests can identify osteoporosis, determine your risk for fractures (broken bones), and measure your response to osteoporosis treatment. The most widely recognized BMD test is a dual-energy x-ray absorptiometry, or DXA test. It is painless—a bit like having an x-ray, but with much less exposure to radiation. It can measure bone density at your hip and spine. BMD tests can:
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 doctor 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 balanced proportion. In particular, calcium and vitamin D are needed for strong bones and 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. Although 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.
Therapeutic medications: Several medications are available for the prevention and/or treatment of osteoporosis, including: bisphosphonates; estrogen agonists/antagonists (also called selective estrogen receptor modulators or SERMS); calcitonin; parathyroid hormone; estrogen therapy; hormone therapy; and a recently approved RANK ligand (RANKL) inhibitor.
Preventing falls 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 or balance, chronic diseases that affect 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 that affect their balance or gait, and that they discuss these changes with their health care provider. Here are some tips to help eliminate the environmental factors that lead to falls.
The National Institutes of Health Osteoporosis and Related Bone Diseases ~
National Resource Center acknowledges the assistance of the National
Osteoporosis Foundation in the preparation of this publication.
This publication contains information about medications used to treat the health condition discussed here. When this publication was produced, we included the most up-to-date (accurate) information available. Occasionally, new information on medication is released.
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