Osteoporosis
Osteoporosis is a disease that slowly weakens the bone, often leading to fractures and disability. According to the National Osteoporosis Foundation, osteoporosis is a major public health threat for 28 million Americans, 80 percent of whom are women. One out of two women and one out of eight men suffers an osteoporosis related fracture. However, the rate of osteoporosis in all people aged 73 and older is identical in both sexes. In the U.S. today, 10 million individuals already have the disease and 18 million more have low bone mass, placing them at increased risk for osteoporosis. Many people are surprised by a diagnosis of osteoporosis, often called the “silent disease”, because bone mass loss occurs over many years without a person’s knowledge. Eventually, bones are weakened enough that a sudden strain, bump or fall can cause a fracture or a vertebra to collapse. Vertebral (spine) fractures can result in a loss of height and stooped posture as well as severe pain. Also, hip fractures may limit an individual’s mobility and can lead to a loss of independence.
HOW DOES OSTEOPOROSIS DEVELOP?
Bones are made up of collagen, a protein that provides a soft framework, and calcium phosphate, which hardens the framework and makes it stronger. The two substances working together give bones the strength plus flexibility they need to withstand stress. Bones constantly undergo a remodeling process that removes old bone and adds new. When calcium levels in the blood fall too low, cells called osteoclasts spring into action to dissolve tiny amounts of bone tissue. This permits calcium to enter the bloodstream where it is used to control heart rate, blood pressure, and muscle contractions. Conversely, cells called osteoblasts then work to fill in these holes with the collagen and calcium phosphate that harden into new bone. Each year this process replaces about 20 percent of our entire skeleton. During childhood bones increase is size and density because more bone is added than removed. Bones cease growing during adolescence, but they continue to become denser until they reach their peak mass at around age 30. After age 35 people begin to lose bone at a rate that is faster than replacement, usually up to 0.5 percent each year. At menopause, when estrogen production plummets, the loss accelerates dramatically. Approximately 2 percent per year of bone mass is lost annually for the first 10 years after menopause. Osteoporosis occurs when too much bone is removed, too little new bone is formed, or both. Osteoporosis is most commonly found in the bones of the spine, hip, and wrist. It is often diagnosed only after a fracture occurs. Osteoporosis is preventable, detectable and treatable. Contrary to popular belief, osteoporosis is not an inevitable part of aging.
WHO IS AT RISK FOR DEVELOPING OSTEOPOROSIS?
For men and women risk factors include:
- A family history of osteoporosis (bone mass is mostly genetically determined)
- Advanced age
- Inactive lifestyle
- Smoking
- Excessive use of alcohol and caffeine
- Long-term use of certain medications including steroids, some anticonvulsants, or excessive thyroid hormone therapy
- Insufficient dietary intake of calcium
- Scoliosis
- Testosterone deficiency in men
For women there are extra risk factors:
- Menopause before the age of 45
- Exercise induces loss of menstrual cycle in extreme female athletes
- Caucasian or Asian heritage
- Underweight and/or having a small bodyframe
HOW IS OSTEOPOROSIS DIAGNOSED?
Osteoporosis is diagnosed through the use of x-rays and/or bone mass measurements in conjunction with physical examinations. Bone mass can be measured through a bone mineral density test of the spine, wrist, and hip. A newer ultrasound device transmits sound waves through the patient’s heel and then analyses the bone density results. This is a very quick method for determining bone density, but unfortunately inaccurate. There is a poor correlation between heel bone density and hip or spine bone density. Sometimes blood tests are ordered to evaluate other possible causes of weakened bone. Unexplained back pain, height loss, fractures resulting from minimal trauma and history of recurrent or non-traumatic fractures increases the suspicion of an osteoporosis diagnosis.
The dotted line in the graph is the fracture threshold. Note how more and more women fall below that line as they age. The blue area is above average and the red area is below average. As you can see, as women age, even average and above average bone density can fall below the fracture line.
HOW DO YOU PREVENT OSTEOPOROSIS?
Proper nutrition and exercise throughout life can dramatically decrease a person’s risk of suffering from osteoporosis. Establishing healthy habits, such as weight bearing exercises and avoidance of behaviors that alter bone cell function (smoking and alcohol intake), are helpful. The best way to prevent osteoporosis is to take calcium, vitamin D and to exercise.
Calcium
Calcium is the primary mineral in your bones. It is critical to the physical structure as well as functioning of the human body. The human body must maintain a constant level of calcium in the blood stream to enable proper functioning of the heart, muscles, and organs. Without a steady supply of calcium in your diet, your body will steal it from the only source it has, your bones. Over time, frequent calcium withdrawals can make bones weak and fragile. This can lead to the crippling disease called osteoporosis, which is a major public health threat for 28 million Americans, particularly women, but also men.
National surveys have shown that many Americans are not consuming enough calcium. Teenage girls, who frequently diet, often consume inadequate dietary calcium needed for building strong bones. The goal is to get plenty of calcium, preferably from dietary sources, and to increase exercise. One way to increase the amount of calcium in you diet is to eat calcium-rich foods like low-fat milk, cheese, broccoli, and others. If you are unable to get enough calcium through your diet, a calcium supplement may be appropriate. Adequate calcium intake is essential to maintain bone strength and can play a vital role in preventing osteoporosis-related fractures. Calcium intake must be spread out through the day for the body to absorb it. Taking calcium one time during the day is not effective treatment or prevention.
See Osteoporosis and Nutrition for more on prevention and diet.
Dietary Reference Intakes for Calcium according to the National Academy of Sciences:
| Age 9 -18 years: | 1,300 mg/day |
| Adults 19-50 years: | 1,000 mg/day |
| Adults over 50 years: | 1,200 mg/day |
| Pregnant or lactating - under 18 years | 1,300 mg/day |
| Pregnant or lactating - 19- 50 years | 1,000 mg/day |
| Postmenopausal women not receiving HRT | 1,500 mg/day |
| Anyone over the age of 65: | 1,500 mg/day |
Natural foods, especially dairy products, are the best source of calcium.
Calcium-rich Foods |
Calcium Content |
| Milk, 8oz glass | 300 mg |
| Yogurt, low fat 8oz | 415 mg |
| Calcium-fortified orange juice, 8oz | 300-350 mg |
| Cottage cheese, 1 cup | 138 mg |
| Cheese, mozzarella, 1oz | 150 mg |
| Cheese, cheddar, 1oz | 200 mg |
| Broccoli, 1 cup | 180 mg |
| Turnip greens, 1 cup | 200 mg |
| Cabbage, 1/2 cup | 21 mg |
| Sweet potato with skin | 286 mg |
| Carrots, 1/2 cup | 23 mg |
| Clams, 3 oz | 65 mg |
| Crab, 3 oz | 64 mg |
| Tofu, 1 cup | 258 mg |
| Salmon with bones, 3 oz | 208 mg |
| Sardines, 3 oz | 267 mg |
Calcium Supplements
Some people do not consume enough calcium from food and may need to take a calcium supplement. The amount of calcium you will need from a supplement depends on how much calcium is consumed from food sources. Several different calcium compounds or salts are used in supplements. It is important to note the actual amount of calcium in the different supplements. When choosing a calcium supplement, stick to brand names with proven reliability. It is best to avoid calcium from bone meal, dolomite, or unrefined oyster shells, as these may contain lead or other toxic metals. If the product has “USP” on the label, this means that it has met voluntary standards of purity and dissolution established by the United States Pharmacopoeia (USP). These products are safe to take and well absorbed by the body. Calcium citrate is easier for the body to absorb and is the calcium of preference for supplements. Calcium carbonate requires the correct acidity in the stomach/intestine or it will not be absorbed!
Nonprescription Calcium Supplements:
| Calcium carbonate (Caltrate 600, Tums 500) | 200, 250, 500, 600 mg/tablet |
| Calcium citrate (Citracal) | 200, 315, 500 mg/tablet |
| Calcium phosphate (Posture D) | 600 mg |
It is very hard to consume too much calcium. A daily intake of 2,500mg poses little risk of adverse effects in most healthy individuals. A few individuals, whose intestines absorb ingested calcium at unusually high efficiencies, may be at risk for kidney stones. If you have a history of kidney stones ask your physician before starting a high calcium diet.
Vitamin D
Vitamin D is essential for optimal calcium absorption and bone health. Vitamin D allows calcium to leave the intestine and enter the bloodstream to reach the bones. It is synthesized in the skin through exposure to sunlight. While most people are able to obtain enough vitamin D naturally, vitamin D production decreases in the elderly, in housebound individuals, and during the winter months. These individuals may require vitamin D supplementation to ensure a daily intake of at least 400 IU, but not more than 800 IU of vitamin D. Milk in the United States is fortified with this vitamin, as are other foods such a breakfast cereals. Good sources of vitamin D are fatty fish and cod liver oil, but the most important source is simply sunlight. One hour of sunlight per day on a Caucasian face provides adequate vitamin D.
Women
Women may consider taking estrogen after menopause. Estrogen replacement therapy (ERT) protects bone during the years of rapid bone loss immediately following menopause. Because estrogen replacement is not without risks, women must discuss the pros and cons of this therapy with their primary care physician or gynecologist. ERT decreases osteoporotic hip fractures and the risk of colon cancer; however ERT may increase the risk of breast cancer, heart attack and stroke. Consult your family physician for treatment options.
HOW IS OSTEOPOROSIS TREATED?
A variety of medications are available to slow bone loss and prevent the fractures caused by osteoporosis. Although there is no cure for osteoporosis, medications are approved by the Food and Drug Administration (FDA) for prevention and /or treatment of osteoporosis. Each of these medications slows or stops bone loss, increases bone density, and reduces fracture risk. Listed below are medications prescribed to prevent and treat osteoporosis.
Calcitonin, sold under the name Miacalcin, is a naturally occurring hormone that is involved in calcium regulation and bone formation. This nasal spray appears to reduce bone loss, especially in the spine. This medicine works best with acute fractures to reduce fracture pain during the first 3 months.
Alendronate, sold under the brand name Fosamax, is a bisphosphonate that also slows or stops bone breakdown and reduces the risk of hip and spine fractures. Also, it is approved for use in men. Once-weekly dosing is available. This drug kills the osteoclast cells which resorb bone thereby allowing the osteoblast cells to make bone. This produces a net increase in bone mass. The problem is that bisphosphonates only increase the bone mass a small amount and the bone that is present is more brittle than normal bone.
Another bisphosphonate, risedronate (Actonel) is used for prevention and treatment of osteoporosis. Once-weekly dosing is possible. Actonel decreases hip and spine fracture risk.
Estrogen replacement therapy (ERT) is a female hormone that protects women from bone loss and reduces fracture risk. ERT also reduces symptoms associated with menopause. One example of ERT is Premarin. Because ERT is not without risks, women must discuss the pros and cons of this therapy with their family doctor or gynecologist.
Raloxifene, brand name Evista, is a newer medication approved for the prevention of osteoporosis. It acts like a low dose of estrogen on bone and prevents bone density loss, thus reducing risk of vertebral fractures. Unfortunately, Evista has no significant effect on non-spine or hip fractures. A patient with a history of blood clots is not a candidate for this medication, since it may increase the incidence of deep vein thrombosis.
Forteo, is an anabolic drug approved in November 2002 by the FDA to treat osteoporosis. Forteo (recombinant human parathyroid hormone) injections are used to increase bone mass in select patients. It decreases the risk of fractures through daily subcutaneous injections. Forteo is approved for use in men and women who have osteoporosis, who are at high risk for osteoporotic fractures, or who have failed or are intolerant of other therapies. This is the best medicine available to increase bone mass and strength, however it may have some side effects which could preclude its use.
The appropriate therapy plan should be discussed with your physician to review risks as well as benefits, along with potential side effects. Several medications are currently under investigation and should expand the treatment options available to patients.
Non-medical osteoporosis preventives and treatments include:
- Adequate calcium intake, either through diet or supplementation
- Weight bearing exercise
- Vitamin D supplementation
- Smoking cessation
- Decrease caffeine and alcohol intake
CONCLUSION:
You can take steps now to prevent broken bones later. By preventing the debilitating effects of bone loss, you can look forward to a healthy, active life. Establishing healthy habits, such as regular exercise and smoking cessation, will contribute greatly to strong bones. If you have already suffered a broken bone, a treatment program can slow further bone loss and reduce the likelihood of additional fractures. If you think you are at risk of or may already have osteoporosis, see your doctor. Your doctor can make a diagnosis and prescribe a treatment program that is right for you. By preventing the debilitating effects of bone loss, you can look forward to a healthy, active life.
