I recently wrote on this blog about how one goes about assessing for osteoporosis. In this article, I will review the recommended treatment for osteoporosis.
Osteoporosis is a common disease of older individuals. It can be diagnosed by measuring one’s bone density, or from a history of a previous fracture occurring with low trauma. Osteoporosis leads to an increased risk of broken bones (fractures), which in an aging population can be associated with both complications as well as accelerated chance of dying.
If you are at risk for osteoporosis, there are several things you can do to prevent a fracture from occurring. Let’s review all of them, so that you know what your options are.
If physically able, you can start with exercise. The most effective exercise is weight-bearing or working against gravity. That would include most exercise like walking, running, weight lifting, or biking. Swimming is not as effective because water removes the effect of gravity.
Calcium is also helpful in reducing the risk of a fracture. It is most effective in the elderly and in children and less helpful during early adulthood and middle age. The recommended amount of calcium is 1200-1500 mg daily between what you can get in your diet and what you take in a supplement.
Most of the calcium in the American diet comes from dairy products including milk, cheese, and yogurt. Ice cream is less helpful because much of the volume is taken up by fat, not calcium containing milk. Each serving of dairy – 8 oz. of milk, 6 oz. of pure yogurt, or an ounce of solid cheese – contains around 300 mg of calcium. Therefore, you would need around 4 – 5 servings a day, which is much more than most people take in.
Supplements, such as calcium carbonate 500 mg, or calcium citrate 500 mg daily – may be necessary. The citrate is said to be better absorbed if you take medication that reduces stomach acid, such as Ranitidine (Zantac) or Omeprazole (Prilosec).
Some recent studies suggest that excess consumption of calcium can cause an increased risk of heart disease and other blood vessel disease. However, at the doses being discussed, it should be safe. Remember, if you have been told that you have a risk for breaking a bone, than your risks for that may exceed your risk for developing heart disease.
The other important nutrient for bone is vitamin D. There is controversy on how much vitamin D is needed. Much of our vitamin D is obtained by exposure to the sun because vitamin D is made in the skin when exposed to UV light. Younger people generally do not have a problem with vitamin D if they experience some sun exposure, perhaps as little as 15 minutes daily. However, older people and some younger people who rarely go out in the sun may not be getting enough exposure to make vitamin D. These people may need a supplement.
The Institute of Medicine recommends 600 units daily for adults up to age 70 and 800 units for those over 70. Some other experts suggest higher doses as high as 2000 units daily. Fortunately, we are finding vitamin D a safe medication and higher doses are not likely to be harmful. As with calcium, I need to emphasize that what is recommended for the general healthy population, is not what may be needed if you have weaker bones.
Magnesium and Phosphorus
Phosphorus is quite easily found in the diet and therefore one rarely needs to supplement. Magnesium on the other hand is less easily obtained from the diet and those individuals with calorie intakes of 1500 or less may benefit from some magnesium, around 250 mg daily, which can be found in multivitamins. However, magnesium has not been shown to reduce the risk of fracture as has calcium and vitamin D and this may be more one of those “why not, it won’t hurt you” type recommendations.
Medications – Estrogen Therapy
Now, let’s talk about beneficial medications for which you would need a prescription. Although still approved for prevention of developing osteoporosis, estrogen therapy for women is effective in reducing the risk of breaking a bone. However, since a large study called the Women’s Health Initiative was published almost 15 years ago, the knowledge of some serious side effects of estrogen has limited its use for osteoporosis. The International Menopause Society thinkgs that treatment for women under age 60 for less than 5 years might be helpful in reducing symptoms of estrogen deficiency and at the same time help reduce bone loss.
Medications – Oral Medications
Since the mid 1990s, a number of oral medications have reached market many of which are now available as generic or non-brand name drugs, which are relatively inexpensive.
To best understand the effectiveness of these medications, it is helpful to understand the concept of risk reduction. As an example, if, out of a group of 100 people, we say that 20 will come down with a cold in the next 4 weeks, that is a risk of 20 percent. If I can offer a medication that reduces that risk to only 10 people getting a cold the relative risk reduction is 50 percent, that is that only half as many people will get a cold. That is called the relative risk reduction. The absolute risk however was 20 percent without treatment and dropped to 10 percent with treatment. Absolute risk is therefore an important concept in trying who to treat, in this discussion, to prevent fractures from occurring.
If I offer you a medication that will reduce your risk of breaking a bone by 50 percent, you need to know what your chance of breaking a bone is in the first place. If that risk is 40 percent over 10 years, let’s say, a 50 percent reduction would bring your absolute risk down from 40 percent to 20 percent. However, if your risk of breaking a bone over 10 years is only 5 percent, the medication would bring it down to 2.5 percent, a degree of reduction which may not justify the possible side effects, the inconvenience and the cost of starting a new medication. In the next sections, I will discuss the relative risk reduction but how the medication can affect you as an individual will depend entirely on your personal risk for breaking a bone. That will vary by the level of your bone density and many other factors such as your age, weight, family history, disease history, and medication history.
Most of the medications that are available work in a similar manner. All except Teriparatide (Forteo), which I’ll discuss last, are considered to be “anti-resorptive” in the way they affect bone. Under normal circumstances, bone is actively changing with some cells, the osteoclasts, removing older bone and another cell type, the osteoblast, laying down new bone. As a result, any damage to the bone such as microscopic cracks are repaired. Anti-resorptives work by slowing down the activity of both of these cells leading to less bone being removed. This “older” bone is felt to continue to collect calcium and other minerals to its surface and as a result becomes stronger over time despite the lack of activity.
A group of medications called bisphosphonates are the most widely used pharmacologic agents for the treatment of osteoporosis. Available in the U.S. since 1995, these anti-resorptives have a long track record for both effectiveness and overall safety. Their structure is similar to a constituent of normal bone called pyrophosphate. Thus, the body handles bisphosphonates much like pyrophosphate and deposits the medication into the bone where is can stay for months to years.
There are four bisphosphonates approved in the United States – Alendronate (Fosamax), Risedronate (Actonel), Ibandronate (Boniva) and Zoledronic Acid (Reclast or Zometa). The first three are available in tablet form and are taken at intervals from every week to once a month. Ibandronate and Zoledronic acid are available for intravenous use, meaning directly into the blood stream, once every three months in the case of Ibandronate and just once per year for Zoledronic Acid.
All of these medications have been shown to reduce the likelihood of breaking a bone often by as much as 50 percent or more.
Medication – Side Effects
In general, these agents have similar side effects. By far the most common problem is stomach upset, either heartburn, or a gnawing type pain. This does not occur with the intravenous medications. Rarely, some individuals will develop a deep aching in their bones, the cause of which is not understood. Both the stomach problems and bone pain will resolve once the medication is discontinued.
After 20 years of experience with these medications, we have noted a couple of rare side effects. These problems have received a significant amount of attention in various publications even though they occur much less often than being injured in an automobile accident. In one situation, the jaw bone can develop a cavity that does not heal easily. This occurs about 1 time per year in 25, 000 people taking the medication. The other side effect is called an “atypical hip fracture.” In this case, we think the bone may not heal small breaks which can eventually lead to a complete break. This complication seems to be related to how long you stay on the medication. If you are on medication for up to five years, the risk of an atypical fracture is about one case per year per every 10,000 people taking the medication and goes up to about 1 in 1000 per year after being on medication for 8-10 years. We have developed a strategy for avoiding both the jaw and hip fracture complications. If after 3-5 years of treatment, the risk of breaking a bone is not excessive, one can stop treatment for one or more years, what we call a “drug holiday.” After the holiday, unless you have improved to a point that treatment is not necessary, treatment is restarted. This cycle is repeated as long as it is felt treatment is appropriate. Remember that the bisphosphonate stays in bone for years. However, by stopping, the risk of the side effect is reduced by 70 percent in the first year although the benefit of taking the medication lingers for a longer period of time.
Another potent, effective, agent is Denosumab (Prolia). Although this is also an anti-resorptive like the bisphosphonates, it does not stay in the bone. Given as an injection under the skin (subcutaneous) twice a year, the medication is broken down within about two weeks although its effect on the bone cells lasts up to six months. It causes no stomach problems, but other side effects seen with bisphosphonates can be seen with this medication. Because it does not stay around in bone, there is a concern that stopping this medication, as we can with a bisphosphonate, could lead to loss of effectiveness and should therefore be avoided.
Raloxifene (Evista) is a less potent agent that works in the body at the same places estrogen can have an effect. It has been shown to reduce the chance of developing spine fractures and can increase bone density at the spine and hip. But, it does not cause the long-term side effects mentioned above, nor does it typically cause stomach issues. It can however cause blood clotting, much like estrogen, which can lead to serious complications such as stroke or blood clot in the lung. However, unlike estrogen, Raloxifene can reduce the risk of breast cancer and appears to have no likelihood of causing heart attacks. It is only approved for females and is generally used shortly after menopause to maintain bone density.
A brief mention of Calcitonin (Miacalcin). This is given by nose spray and is well tolerated. However, it is a very weak agent with minimal benefit. There have been recent concerns about it increasing cancer risk, and in Europe the drug regulators have taken it off the market.
Finally, a word about Teriparatide (Forteo). Unlike all of the above agents, Teriparatide is not an anti-resorptive. It works by stimulating the bone forming cell, the osteoblast, which increases the amount of bone that is made. This can lead to a significant reduction in the risk of fracturing. It is most effective in the first 18-24 months and at that time it is stopped and an anti-resorptive started to keep the improvement from disappearing which it does quickly once Teriparatide is stopped. It has minimal side effects, but must be given by daily injection under the skin, much like insulin for diabetes. It is also very expensive compared to the other medications. During early studies on the medication, it was found that growing rats given the injections at very high dose developed a type of bone tumor called osteosarcoma. Fortunately, several studies since then have not shown a similar problem in humans. However, this development prompted the FDA to limit the medications use to 24 months. As it turns out, going beyond that time may not be all that helpful anyway and adding another medication as a tail seems to work well.
Hopefully, those of you at risk for osteoporosis will talk to your provider about getting a bone density study and be evaluated for your chance of breaking a bone. If you and your provider reach the conclusion that treatment may be beneficial, I hope this discussion can help in your decision-making.
Edward Leib, MD, a rheumatologist, is medical director of the Osteoporosis Center at the University of Vermont Medical Center, where he is also a emeritus professor in the Larner College of Medicine at UVM.