An Overview of Osteoporosis
By National Institutes of Health
Osteoporosis (Degenerative Arthritis), or porous bone, is a disease characterized by low bone mass and structural deterioration of bone tissue, leading to frail bones 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.
Facts and Figures
- Osteoporosis is a major public health threat for 44 million Americans, 68 percent 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 have 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, approximately 700,000 vertebral fractures, 250,000 wrist fractures, and more than 300,000 fractures at other sites.
- Based on figures from hospitals and nursing homes, the estimated national direct expenditures for osteoporosis and related fractures total $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 both flexible and strong, which in turn helps it 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 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 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.
Risk Factors that Contribute to Osteroporosis in Seniors
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. There are some you cannot change and others 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 faster than men because of the changes that happen with menopause. However, men do get osteoporosis.
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.
- Ethnicity - Caucasian and Asian women are at highest risk. African American and Hispanic women have a lower but significant risk.
- Family history - Fracture risk 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.
Risk factors you can change
- Sex hormones - Abnormal absence of menstrual periods (amenorrhea), low estrogen level (menopause), and low testosterone level 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 and fractures.
- Lifestyle - An inactive lifestyle or extended bed rest tends to weaken bones.
- Cigarette smoking - Cigarettes are bad for bones as well as the heart and lungs.
- Alcohol intake - Excessive consumption increases the risk of bone loss and fractures.
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 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).
Detecting and Preventing Osteoporosis
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 bone mineral density test is called 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.
What a bone test does
- Detects low bone density before a fracture occurs.
- Confirms a diagnosis of osteoporosis if you already have one or more fractures.
- Predicts your chances of fracturing in the future.
- Determines your rate of bone loss, and/or monitor the effects of treatment if the test is conducted at intervals of a year or more.
Treating and Preventing Osteoporosis
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.
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. 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. 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.
Vitamin D plays an important role in calcium absorption and in bone health. It is made 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 for people in general during the winter. Depending on your situation, you may need to take vitamin D supplements to ensure a daily intake of between 400 to 800 IU of vitamin D. Massive doses are not recommended.
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. Bone loss can also result from long-term treatment with certain antiseizure drugs - such as phenytoin (Dilantin1) 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 physician and not to stop or change your medication dose on your own.
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 they often go through menopause earlier. Smokers also may absorb less calcium from their diets.
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, because of both poor nutrition and increased risk of falling.
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, stair climbing, weight training, tennis, and dancing.
Various medications are available for preventing and treating osteoporosis.
The National Institutes of Health (NIH), a part of the U.S. Department of Health and Human Services, is the primary Federal agency for conducting and supporting medical research. NIH annually invests over $28 billion in medical research.