Osteoporosis is a bone disease where parts of the bone weaken, increasing the risk of bone fractures. The disorder is especially associated with the aging process though it affects men and women of all ages. It's responsible for a large number of fractures in the elderly, as the weakened bones can no longer support body weight.
The disease especially affects women who have reached menopause, although men are also affected. In general, women have 30% less bone mass than men, so they're more at risk. After menopause, when the hormone estrogen stops being produced by the ovaries, women lose bone mass more quickly. By the age of 65 to 70 years, men and women lose bone at about the same rate. Eating enough calcium and vitamin D and participating in weight-bearing exercise are important steps in preventing osteoporosis.
Bone is made up mostly of minerals. The bones in our bodies are constantly being replaced with new bone. This cycle takes about 100 days and is influenced by the hormones we produce in our bodies (such as estrogen in women) as well as by calcium and vitamin D. Osteoporosis occurs when bone tissue and minerals are lost faster than the bone is replaced.
There are two main types of osteoporosis: primary osteoporosis and secondary osteoporosis.
Primary osteoporosis is most common in women aged 50 to 65 years who have reached menopause. It affects twice as many females as males over the age of 75 years.
Secondary osteoporosis can affect young and middle-aged people as well and may be caused by:
- medications such as corticosteroids (e.g., prednisone)
- anorexia nervosa, a self-inflicted starvation which leads to malnutrition
- too much exercise - women who exercise excessively may stop their menstrual cycle and the production of the hormone estrogen in their ovaries
Certain factors that may increase the risk of osteoporosis include:
A drop in estrogen after menopause. For women, the percentage of bone that is lost increases after menopause. This is because the ovaries stop producing estrogen, an important hormone in the bone repair process. Female athletes and women who suffer from anorexia nervosa may also be at risk for osteoporosis. In both cases, the menstrual cycle is disrupted or even stopped. The levels of estrogen in the body therefore drop drastically. Women who had early menopause (before the age of 45 years) or who did not have any children also are at a higher risk.
Physical, family, and lifestyle factors. Small, thin, pale-skinned people as well as people with elderly relatives who have suffered numerous bone fractures are at risk. Lifestyle factors such as smoking and excessive drinking can also increase the risk. Certain medications and some diseases such as diabetes also may contribute to bone loss. People of European and Asian descent are most at risk.
Lack of exercise. Bones need to be used daily in order to stay healthy. People who stay active are less at risk for developing osteoporosis, as their bones are stronger and less bone is lost with age. A person who is bed-ridden or inactive for a lengthy period of time loses bone mass very quickly and is, unfortunately, also at risk.
Lack of calcium. Children, adolescents, and adults need to eat the recommended amounts of vitamins and minerals. Calcium and vitamin D are the most important in preventing osteoporosis, as they help bones stay healthy and strong in later life.
Osteoporosis itself does not cause symptoms.However, weakened bones, no longer able to support body weight, can break under the slightest pressure. Fractures of the hips, wrists, or spinal vertebrae are the most common. Hip fractures are more frequent in both men and women over the age of 75 years. A hairline break in the spinal cord may go unnoticed, even when X-rayed, and cause little or no pain. A spinal crush fracture, where the vertebral column crumbles or collapses, is much more painful and can lead to deformed posture. Other signs of osteoporosis may include a sharp pain in the back while doing regular activities around the house, or while coughing, laughing, or sneezing. Pain may even be felt when standing still.
The first step in diagnosing osteoporosis is to rule out certain causes such as diseases and drugs that are known to contribute to bone loss.An examination to determine such causes might include blood and urine tests to measure the levels of certain hormones produced in the body. It is also important to know how much calcium and vitamin D is consumed.
There are several effective and relatively quick methods by which to determine bone density. A computerized tomography(CT) scan is one way to check the condition of bones. Measuring bone density by a method called DEXA (dual energy X-ray absorptiometry) is an effective way to assess the risk of osteoporosis. Scanning parts of the body such as the hips or spine with a slow-moving X-ray machine can confirm whether there's an increased risk of fracture.
People with a family history of osteoporosis, those suffering from anorexia nervosa, and those taking medications (e.g., corticosteroids) that increase the risk are recommended to undergo a bone density test. These tests are done every one to two years in people who are already getting treatment for osteoporosis, to check on how treatment is working.
TREATMENT AND PREVENTION
There are several treatments for osteoporosis , though prevention is by far the best strategy to fight the disease. Maintaining the strength of bones early on means eating enough calcium on a daily basis. The Osteoporosis Society of Canada recommends 1,000 mg elemental calcium daily for men and women aged between 19 and 49 years, and 1,000 mg to 1500 mg for men and women over the age of 50 years. (Post-menopausal women not taking hormone replacement therapy should have 1,500 mg elemental calcium daily). The Osteoporosis Society of Canada also recommends doing regular weight-bearing exercise, and keeping a healthy lifestyle such as not smoking or drinking alcohol to excess. Vitamin D, in daily doses of 400 IU to 800 IU, is also recommended in the treatment of osteoporosis. Vitamin D is necessary so the body can utilize calcium properly.
Despite preventative measures, drug treatments are still needed to help combat osteoporosis. A variety of hormone-replacement therapies (HRTs) are available for women who have reached menopause. Estrogen replacement helps to preserve the bone for as long as the drug treatment is followed. For the greatest benefit, HRT should start soon after menopause and continue into late life. However, it is never too late to start. Selective estrogen receptor modulators (SERMs) such as raloxifene*, may be used in some women as an alternative to estrogen replacement.
A group of drugs called bisphosphonates (e.g., alendronate, etidronate) slows down bone loss and helps repair bone, reducing the chances of fracture. Calcitonin, a hormone that's made by the thyroid gland, has been shown to help strengthen bones and can be injected or taken through a nasal spray. In some cases, two or more medications are combined in the treatment of osteoporosis.
Weight-bearing exercises also play a role in strengthening bones and preventing fractures in the elderly. Posture and balance can be improved through exercise such as walking and can reduce the risk of hip fractures. Moderate exercise such as walking 45 to 60 minutes three to five times weekly is considered safe and reasonable.