Overview
Osteoporosis is a bone disease where parts of the bone become weak and prone to fracture. This condition is more common in seniors, but can affect men and women of all ages. Osteoporosis is responsible for a large number of bone fractures that occur in seniors, as the weakened bones can no longer support their body weight.
While men also develop osteoporosis, this condition is particularly common among women who have reached menopause. The increased risk at menopause reflects the fact that the hormone estrogen, a key factor in maintaining bone strength in women, is no longer produced by the ovaries after menopause. Because women have 30% less bone mass then men, women are particularly prone to osteoporosis as they age. However, by the age of 65 to 70 years, men and women lose bone at about the same rate. Eating enough food rich in calcium and vitamin D, and participating in weight-bearing exercise are important steps in preventing osteoporosis.
Causes
Bone is made up mostly of minerals such as calcium. The bone in our bodies is constantly being broken down and replaced with new bone. This bone-building cycle takes about 100 days and is influenced by the hormones produced in our bodies (such as estrogen in women) as well as by the levels of 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 and secondary.
Primary osteoporosis occurs most commonly in women after menopause. Osteoporosis affects twice as many females over the age of 70 years as males in the same age group.
Secondary osteoporosis can affect young and middle-aged people as well. It may be caused by:
- medications such as corticosteroids (e.g., prednisone*)
- chronic illnesses such as anorexia nervosa (a self-inflicted lack of food which leads to malnutrition)
- too much exercise - women who exercise excessively may lose their menstrual cycle and stop the normal production of estrogen by the ovaries
Factors that may increase the risk of osteoporosis include:
A drop in estrogen after menopause. The rate of bone loss increases significantly after menopause because the ovaries stop producing estrogen, a hormone that plays a major role in the bone repair process. Female athletes and women who suffer from anorexia nervosa may also be at increased risk for osteoporosis. In both cases, the menstrual cycle is disrupted or lost and levels of estrogen in the body drop dramatically. Women who experience early menopause (before the age of 45 years) or women who have not had any children are more likely to have osteoporosis.
Family history and body type. Osteoporosis tends to run in families and the risk of this condition may be greater for individuals with elderly relatives who have had more than one bone fracture. People of European and Asian descent are most at risk. People who are thin or "small-boned" also have a higher risk of osteoporosis.
Lifestyle factors and health conditions. Lifestyle factors such as smoking and excessive drinking, taking specific medications (such as corticosteroids), and having certain diseases may also contribute to bone loss. People with type 2 diabetes are more likely to suffer a hip or shoulder fracture than those without diabetes.
Lack of exercise. Bones need to be used daily in order for them to stay healthy. People who are physically active are less at risk of developing osteoporosis, as their bones are stronger and less likely to lose strength with age. By contrast, a person who is bed-ridden or inactive for a lengthy period of time loses bone mass very quickly and is at high risk of osteoporosis.
Lack of calcium. Children, adolescents, and adults need to eat the recommended amounts of vitamins and minerals. Calcium and vitamin D are very important in the maintenance of healthy and strong bones throughout life and in the prevention of osteoporosis.
Symptoms
Osteoporosis itself does not usually cause noticeable symptoms. However, weakened bones that are no longer able to support body weight can break under even slight pressure. Such fractures most commonly occur in the hipbones, wrists, or spine. Hip fractures are more frequent in people over the age of 75 years. Some fractures caused by osteoporosis, such as hairline breaks in the spine, may cause little or no pain and may go unnoticed, even when they show up on an X-ray.
By contrast, spinal crush fractures, where the vertebral column crumbles or collapses, are much more painful and can lead to deformed posture. Another symptom caused by osteoporosis is chronic back pain. This pain can worsen even when you are making small movements such as regular activities around the house, or while coughing, laughing, or sneezing. You may even feel pain when you are standing still.
Treatment
There are several treatments for osteoporosis, but prevention is by far the best strategy to fight the disease. Maintenance of good bone strength requires that you have a regular intake of calcium.
The Osteoporosis Society of Canada recommends 1,000 mg elemental calcium daily for men and women aged between 19 and 50 years, and 1,500 mg for men and women over the age of 50 years. Postmenopausal women not taking hormone replacement therapy should have 1,500 mg elemental calcium daily. The Osteoporosis Society of Canada also recommends regular weight-bearing exercise and a healthy lifestyle with no smoking or excessive intake of alcohol. Vitamin D in daily doses of 400 IU to 800 IU is also recommended in the treatment of osteoporosis to help increase calcium absorption in the bones.
Weight-bearing exercises play a role in strengthening bones and preventing fractures. Posture and balance can be improved through exercise and can significantly reduce the risk of bone fractures. Moderate exercise, such as walking 45 to 60 minutes three to five times weekly, is considered a safe and reasonable strategy to prevent osteoporosis.
Despite better understanding of how osteoporosis may be prevented, drug treatments are still needed to help fight this condition.
The bisphosphonates (e.g., alendronate, etidronate, risedronate) are one of the main groups of medications that may be used to prevent and treat osteoporosis. These medications slow down bone loss and help repair bone, reducing the chance of fracture. Selective estrogen receptor modulators (SERMs) such as raloxifene, may also be used to prevent and treat osteoporosis in women.
Calcitonin, a hormone normally produced by the thyroid gland, has also been shown to strengthen bone and can be injected or taken through a nasal spray. Two or more medications may also be used in combination to treat some cases of osteoporosis.
A variety of hormone-replacement therapies (HRTs) are available for women who have reached menopause. Estrogen replacement helps to preserve bone, but the therapy has a number of health risks. If you are taking or are considering taking HRT, talk to your doctor about the risks and benefits.
*All medications have both common (generic) and brand names. The brand name
is what a specific manufacturer calls the product (e.g., Tylenol®).
The common name is the medical name for the medication (e.g., acetaminophen).
A medication may have many brand names, but only one common name. This article
lists medications by their common names. For more information on brand names,
speak with your doctor or pharmacist.
Other tips:
The first step in diagnosing osteoporosis involves evaluating your bone density. If the bone density is too low, you will be diagnosed with osteoporosis. There are several effective and relatively quick methods for measuring bone density. Bone density measurement by a method called DEXA (dual energy X-ray absorptiometry) is the most effective way to assess the risk for osteoporosis. Scanning parts of the body such as the hips or spine using a special type of X-ray machine can confirm you have an increased risk of fractures. Computerized tomography (CT) scans can also be used to check the condition of the bones.
Following the diagnosis of osteoporosis, further studies are needed to look for possible causes. An examination to determine such causes might involve blood and urine tests to measure the levels of certain hormones produced in the body as well as questionnaires on lifestyle and diet, to determine, for example, one's daily intake of calcium and vitamin D.
People who have a family history of osteoporosis, those suffering from anorexia nervosa, and those taking medications such as corticosteroids (that increase the risk for this condition) are recommended to undergo bone density testing even if they have no symptoms. Bone density testing is conducted every one to two years for people already receiving treatment for osteoporosis, to check how the treatment is working.
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