Osteoporosis Health Article

Definition

The word osteoporosis literally means "porous bones." It occurs when bones lose an excessive amount of their protein and mineral content, particularly calcium. Over time, bone mass, and therefore bone strength, is decreased. As a result, bones become fragile and break easily. Even a sneeze or a sudden movement may be enough to break a bone in someone with severe osteoporosis.

Description

Osteoporosis is a serious public health problem. Some 28 million people in the United States are affected by this potentially debilitating disease, which is responsible for 1.5 million fractures (broken bones) annually. These fractures, which are often the first sign of the disease, can affect any bone, but the most common locations are the hip, spine, and wrist. Breaks in the hip and spine are of special concern because they almost always require hospitalization and major surgery, and may lead to other serious consequences, including permanent disability and even death.

To understand osteoporosis, it is helpful to understand the basics of bone formation. Bone is living tissue that is constantly being renewed in a two-stage process (resorption and formation) that occurs throughout life. In the resorption stage, old bone is broken down and removed by cells called osteoclasts. In the formation stage, cells called osteoblasts build new bone to replace the old. During childhood and early adulthood, more bone is produced than removed, reaching its maximum mass and strength by the mid-30s. After that, bone is lost at a faster pace than it is formed, so the amount of bone in the skeleton begins to slowly decline. Most cases of osteoporosis occur as an acceleration of this normal aging process—a form referred to as primary osteoporosis. The condition can also be caused by other disease processes or prolonged use of certain medications that result in bone loss—a form called secondary osteoporosis.

Osteoporosis occurs most often in older people and in women after menopause. It affects nearly half of all men and women over the age of 75. Women, however, are five times more likely than men to develop the disease. They have smaller, thinner bones than men to begin with, and they lose bone mass more rapidly after menopause (usually around age 50), when they stop producing a bone-protecting hormone called estrogen. In the five to seven years following menopause, women can lose about 20% of their bone mass. By age 65 or 70, though, men and women lose bone mass at the same rate. As an increasing number of men reach an older age, they are becoming more aware that osteoporosis is an important health issue for them as well.

Causes and symptoms

A number of factors increase the risk of developing osteoporosis. They include:

• Age. Osteoporosis is more likely as people grow older and their bones lose tissue.
• Gender. Women are more likely to have osteoporosis because they are smaller and so start out with less bone. They also lose bone tissue more rapidly as they age. While women commonly lose 30–50% of their bone mass over their lifetimes, men lose only 20–33% of theirs.
• Race. Caucasian and Asian women are at higher risk for the disease than women of African or Hispanic ethnicities.
• Figure type. Women with small bones and those who are thin are more liable to have osteoporosis.
• Early menopause. Women who stop menstruating early because of heredity, surgery or a lot of physical exercise may lose large amounts of bone tissue early in life. Conditions such as anorexia and bulimia may also lead to early menopause and osteoporosis.
• Lifestyle. People who smoke or drink too much, or do not get enough exercise have an increased chance of getting osteoporosis.
• Diet. Those who do not get enough calcium or protein may be more likely to have osteoporosis. People who constantly diet are more prone to the disease. It has been shown that adolescent girls (but not boys) have insufficient calcium intake levels in the diet. This calcium deficiency occurs during a period of rapid bone growth, stunting the peak bone mass ultimately achieved; thus, these individuals are at greater risk of developing osteoporosis.
• Genetics. People with a family history of osteoporosis are more likely to contract the disease.
• Chronic use of medication. Certain types of medication, such as steroids, interfere with the body's ability to absorb calcium or accelerate calcium depletion, damaging bone density.

Osteoporosis is often called the "silent" disease, because bone loss occurs without symptoms. People often do not know they have the disease until a bone breaks, frequently in a minor fall that would not normally cause a fracture. A common occurrence is compression fractures of the spine. These can happen even after a seemingly normal activity, such as bending or twisting to pick up a light object. The fractures can cause severe back pain, but sometimes they go unnoticed—either way, the vertebrae collapse down on themselves, and the person actually loses height. The hunchback appearance of many elderly women, sometimes called "dowager's hump" or "widow's hump," is due to this effect of osteoporosis on the vertebrae.