Millions of Americans have osteoporosis, but while this common condition is both preventable and treatable, it often goes undetected because it has no symptoms.
In medical textbooks osteoporosis is defined as "a disease characterized by low bone mass and microarchitectural deterioration of bone tissue, leading to enhanced bone fragility and a consequent increase in fracture risk." In essence this means that osteoporosis is a disease in which the bones become thin (or brittle) and therefore can break more easily. Osteoporosis results in 1.5 million fractures each year.
Bone is a living tissue that is constantly changing. Throughout childhood and adolescence, bone density increases. (Bone density is also referred to as bone mineral density or bone mass, and can be thought of as "bone strength.") This continues until approximately 25 or 30 years of age when peak bone mass is reached. This maximum bone mass varies from person to person, but in general, women reach a lower peak bone mass than men. After this peak is reached, bone mass begins to decline, and each year the bone becomes a little bit less dense (or less strong). When women go through menopause and estrogen levels fall, there is an accelerated loss of bone that can last for 5-10 years.
There are no symptoms of osteoporosis. Most people, therefore, are unaware that they have it until they sustain a fracture. (Many people confuse osteoporosis with osteoarthritis but these are very different conditions. Osteoarthritis is the most common type of arthritis, causing pain and stiffness in affected joints, whereas osteoporosis is a thinning or weakening of the bones and can lead to fractures.)
The danger of osteoporosis lies in the fractures that can result. Vertebral (or spinal) fractures are the most common consequence of osteoporosis and often cause back pain. As a person has more spinal fractures, he or she may develop a "dowager's hump," a protuberant abdomen, and as much as 4 to 8 inches in height loss. However, it is hip fractures that are the most serious outcome of osteoporosis. Up to 20% of people who have a hip fracture die within one year and more than 50% of the survivors are unable to return to independent living. The pain and loss of independence caused by fractures can result in poor self-esteem, depression, and a feeling of hopelessness.
Who is affected?
Approximately 10 million Americans have osteoporosis and an additional 18 million Americans have low bone mass which may progress to osteoporosis. Although anyone can develop the disease, a number of risk factors have been identified.
Age: As people age they are more likely to develop osteoporosis and have fractures.
Gender: Women are more likely to have osteoporosis than men. In fact, 80% of those affected are women. This happens for several reasons. Women tend to reach a lower peak bone mass than men during the growing years and, in addition, often lose bone rapidly when they go through menopause and their estrogen levels fall.
Family history: An individual whose first degree relative has had osteoporosis is at increased risk.
Estrogen deficiency: Menopause before 45 years of age or absence of periods for greater than 1 year in premenopausal women increases the risk of osteoporosis.
Having a thin, lean body build
Excessive alcohol use
Low calcium intake
Diseases such as hyperthyroidism (overactive thyroid), hyperparathyroidism, intestinal malabsorption, diabetes, and rheumatoid arthritis
Medications such as glucocorticosteroids (also called "steroids" -- these include medicines such as prednisone and medrol), dilantin, too much thyroid medicine, and heparin.
History of a fracture during adulthood -- this increases a person's chance of having additional fractures.
Even people with no risk factors can develop osteoporosis. As the bone becomes less dense (and therefore less strong), the risk of fracture progressively increases. Low bone mass has a very strong association with fracture. Osteoporosis can be thought of as a silent risk factor for fracture in much the same way that high blood pressure is a risk factor for stroke and high cholesterol is a risk factor for heart attack. Because osteoporosis causes no symptoms (until the first fracture occurs), it frequently goes undetected unless a test is performed to measure bone density.
Currently, DXA (dual-energy x-ray absorptiometry) is considered the best clinically available method to measure bone mineral density. In this test, a person lies down with the knees and legs elevated. The machine delivers a low dose of radiation (less than that delivered with a standard chest x-ray) and measures the bone density at several sites (typically the hip and the low back or the forearm). DXA provides several pieces of information: 1) the patient's bone mineral density at each area measured; 2) a comparison of the bone density to that of other people of the same age and gender; and 3) a comparison of the bone density to that of young normal adults of the same gender (who represent "peak bone mass"). Based on these results the patient can be categorized as having normal bone mass, osteopenia (low bone mass), or osteoporosis.
There are many other techniques available to measure bone mass, including quantitative computed tomography, ultrasound, and small DXA units that measure bone mass at sites such as the forearm, finger, and heel.
Who should have a bone density test?
The National Osteoporosis Foundation (NOF) recommends that the following groups of people have bone density testing performed:
All women 65 years of age or older
All postmenopausal women who have at least one additional risk factor for osteoporosis
All postmenopausal women who have had a fracture
Women who are considering treatment for osteoporosis but want bone density results before making a decision
Women who have been on estrogen for a long time.
Prevention and Treatment
Bone mass can be maximized in two ways: by increasing accumulation of bone during the growing years (leading to a higher peak bone mineral density) and by minimizing bone loss afterwards. Therefore, prevention of osteoporosis should ideally start during childhood and continue throughout life. Calcium is considered the building block of the bone and is therefore extremely important to the good health of the skeleton. Most Americans consume less than 50% of the daily recommended allowance of calcium. The NIH (National Institutes of Health) Consensus Panel has made the following recommendations for daily calcium intake:
Children and young adults
Pregnant or nursing
25-49 years (premenopausal)
50-64 years (postmenopausal) takingestrogen
50-64 years (postmenopausal) nottaking estrogen
An easy way to estimate your dietary calcium intake is by starting with 300 mg (from breakfast, lunch and dinner) and then adding 300 mg for each dairy exchange product that you eat in a day. A variety of calcium supplements (such as calcium pills and Tums) are available for people who find it difficult to take in enough calcium through diet alone.
Vitamin D is important because it helps the intestine absorb calcium. Many people get enough vitamin D through sun exposure (which stimulates the skin to make vitamin D) and dairy products that are fortified with vitamin D. The elderly (or younger people who may not be getting enough vitamin D) can supplement vitamin D by taking calcium pills that contain vitamin D or by taking multivitamins.
Whereas inactivity is a risk factor for osteoporosis, weight-bearing exercise can help increase peak bone mass during the growing years and slow bone loss in adults. Exercise can also increase strength and coordination, and thereby help prevent falls that can lead to fractures. People who have medical problems or who have had fractures should consult their physician and consider seeing a physical therapist before embarking on an exercise program.
Cigarette smoking and excessive use of alcohol should be discontinued since these are both risk factors for bone loss.
Estrogen deficiency is a strong risk factor for bone loss in women. Replacement of estrogen is an effective way to prevent or slow bone loss in postmenopausal women. There is some evidence that when estrogen is started close to the time of menopause, there is a 50% or greater reduction in the incidence of fractures. Estrogen has some other important benefits besides its effect on bone. It helps control menopausal symptoms such as vaginal dryness and hot flushes. It lowers cholesterol (and also raises HDL while lowering LDL levels). Some studies have shown that it significantly reduces the risk of heart disease; this is being studied further.
If estrogen is given without progesterone (another hormone), there is an increased risk of cancer of the uterus. However, if progesterone is given with the estrogen, there is not an increase in this type of cancer. Estrogen can cause side effects such as fluid retention, breast tenderness, and headaches. A controversial issue is whether or not estrogen increases the risk of breast cancer. Some studies suggest that there is a slightly increased risk of breast cancer in women who have taken estrogen for more than 5-15 years and that it also slightly increases the risk of deep vein thrombosis (blood clots).
The risks and benefits of estrogen therapy should be considered for each woman at the time of menopause. Because of the other health benefits that it offers, estrogen is generally considered the first-line therapy for the prevention and treatment of osteoporosis.
Fosamax (Alendronate sodium ) is a medication that has been approved by the Food and Drug Administration for both the prevention and treatment of osteoporosis in postmenopausal women. It has been shown to increase bone mass in the spine, hip, and total body, and to reduce the risk of fractures in the spine, hip, and wrist.
Fosamax should be taken with 6-8 ounces of plain water on an empty stomach, at least 30 minutes before the first food, beverage or oral medication of the day. If Fosamax is taken with anything other than plain water, it is not absorbed well. After the person takes Fosamax, he or she should not lie down for at least 30 minutes to reduce the chance of irritating the esophagus. Possible side effects include heartburn, chest pain, and difficulty swallowing.
Fosamax is considered an excellent alternative for people who cannot or will not take estrogen.
Miacalcin (Calcitonin) is a medication delivered as a nasal spray; it can also be administered as an injection. Miacalcin nasal spray has been approved by the Food and Drug Administration for the treatment of osteoporosis in women who have been postmenopausal for at least 5 years. Calcitonin has been shown to reduce the risk of fractures in the spine, although so far, studies have not shown that Miacalcin reduces hip fractures. There have been reports that calcitonin helps reduce pain, and therefore it is sometimes helpful for people who have recently had painful fractures. Miacalcin is generally considered safe, but also less effective than estrogen or Fosamax.
Evista (Raloxifene) is a SERM (selective estrogen receptor modulator) that is sometimes described as a "designer estrogen." Evista has been approved by the Food and Drug Administration for the prevention of osteoporosis in postmenopausal women. This medicine has estrogen-like effects on some areas of the body and anti-estrogen effects on other areas. Evista increases bone mass in the spine, hip, and total body by small amounts, and has been shown to reduce fractures in the spine. At this time studies have not shown that Evista reduces hip fractures.
Like estrogen, Evista lowers cholesterol and LDL, but it differs from estrogen in several ways. It does not cause vaginal bleeding or breast tenderness but it increases hot flashes. Preliminary data show a reduction in the risk of breast cancer with Evista (over a median of 30 months) and no increase in the risk of endometrial cancer. Like estrogen, Evista slightly increases the risk of deep vein thrombosis (blood clots).
Osteoporosis is a common disease that is both preventable and treatable. It is a "silent" condition that is best detected with a bone density measurement test. Four medications are approved for the prevention and/or treatment of osteoporosis, and there are also many new therapies on the horizon. The goal of both patients and doctors should be to identify low bone mass and start appropriate treatment early so that fractures can be prevented.