A Medical Approach to Detecting and Treating Osteoporosis

Bone Density Testing

Bone density screening is an important tool used to help analyze bone health.  Dual energy bone densitometry (DEXA) is the current gold standard bone density test, costing anywhere from $150 to $300. DEXA uses a very low dose of radiation (1/1000 of a regular spine x-ray) and measures density in the spine and hips. The bone density is then charted on a graph to see how it stacks up against normal bone densities for a given age. The World Health Organization classifies normal density as being from 0 to -1.0. Osteopenia is from -1.0 to -2.5, and osteoporosis is classified as being less than -2.5. One reading won't tell you the whole truth. A second test is needed at least six months apart to determine if your bone density is increasing, decreasing, or remaining the same. The accuracy and precision of these screenings is also dependent on using the same DEXA machine every time since each DEXA machine can be calibrated differently and thus give different readings. Also, small-boned women may register on the low end of a DEXA test even if their bones are not at risk.

Since there are no standard bone density levels that are deemed high, low, or normal for everyone, it is suggested that women get a baseline density reading at age 40. This will enable you to compare your own readings and whether or not you need to make adjustments in your bone health routine as you start to reach menopause.

So that you won't have to wait six months or longer to know if your bone density program is working, you can also monitor your progress with a simple urine test. Certain bone breakdown products can be measured in the urine to show how fast a person is losing bone. If there are too many of these markers in the urine, you may very well be losing bone faster than is healthy. Test kits are available without a prescription, and results can be mailed directly to your home. I have personally used Aeron Life Cycles for the Pyrilinks urine test and found them very efficient. You can call them toll free at 877.442.3766 or visit their website at www.aeron.com. They suggest repeating the test until the rate of bone resorption returns to normal.

Quantity is not the same as Quality

The DEXA scan cannot measure a person's bone quality or strength. We do not have the technology to test for bone strength. Therefore, a person may be low in bone mass but have perfectly normal bone structure and strength. Yet despite these shortcomings of bone density testing, it is still valuable as an index of the effectiveness of any osteoporosis therapy you may be receiving. I would like to point out that for those taking any of the bisphosphonates which inhibit the breakdown of old bone (as discussed below), the bone density will read higher even though the skeleton will be composed of older bone of less tensile strength. Other than that, a rise in bone density while on osteoporosis therapy is indeed a sign of bone improvement.  Also, remember not to panic at an initial low reading. The reading may or may not be entirely accurate, isn't necessarily predictive of a fracture, and there are several courses of action you can employ to improve low bone density.

Pharmacological Drugs

Bisphosphonates

Your bones contain specialized cells called osteoblasts and osteoclasts. The osteoclasts break down old bone while the osteoblasts build new bone. During menopause, a woman's system loses this natural balance as the osteoblasts slow down the production of new bone and the osteoclasts start breaking down bone faster.

The two most commonly prescribed drugs used to deal with this rapid bone resorption are the bisphosphonates, Fosamax and Actonel. Their mode of action is similar to that of estrogen, which inhibits the osteoclasts or resorption of bone. However, while estrogen merely slows down the osteoclasts, the bisphosphonates actually kill them. Since the older bone is not being removed, the bone becomes much denser, and this denser bone does not translate into a stronger bone. Because no new bone has been laid down, the bones are comprised of older cells that are weak and brittle. The latest FDA approved bisphosphonate drug is Boniva, a once-a-month treatment, which is also essentially a metabolic poison that will kill the osteoclast cells in the bone.

Bone building is a fine balance; the resorption of old bone is what triggers the activity of osteoblasts to build new bone.  Hence, new bone can only be built after old bone is removed. When bone removal ceases, the bone remodeling process ceases.

With bisphosphonates, bone density is shown to increase in the first year. This is actually due to no more bone loss. Continued use of the drugs however shows a plateau effect, since new bone is no longer being made. There are concerns that long-term use of bisphosphonates will produce an older skeleton with increased fragility, particularly in the hip. Osteoporosis expert Dr. Susan Ott advises, “In adult women with osteoporosis, the bisphosphonates are effective for 4.5 years…there might be more vertebral fractures during years 6 to 7.”

In addition, side effects may include heartburn, nausea, abdominal pain, and ulcers. About 12% of the women who take these drugs require additional medical treatment for these disturbances. Also, bisphosphonates can remain in the body for more than 10 years after ceasing treatment. Because of this, some experts are advising great caution in prescribing these drugs to younger or premenopausal women.

Calcitonin

Calcitonin, a hormone secreted from the thyroid gland, has been shown to slow bone loss and increase bone density in the spine. Calcitonin levels are lower in women than in men and tend to decrease with advancing age. Women with osteoporosis have been shown to have lower levels compared to women without the disease.

Calcitonin is the most expensive treatment for osteoporosis. Calcimar (synthetic calcitonin) is received by injection at a cost of $7.50 a day (or more than $2,700 per year). Side effects include transient facial flushing, nausea, and inflammation at the site of injection. On rare occasions, it has caused severe allergic reactions, including anaphylactic shock. Calcitonin is also available in the form of a nasal spray but is not as well absorbed. A runny nose has been the only reported side effect of the spray.

Selective Estrogen Receptive Modulators (SERMS)

SERMS, such as Evista, provide the benefits of estrogen without causing an increase of cancer cells in the uterus or breast. Evista has been shown to increase bone mineral density and reduce vertebral fractures, but there is no evidence that it will prevent hip fractures. However, Evista can increase hot flashes and leg cramps and also poses an increased risk for venous thrombosis or clotting--similar to that found with Hormone Replacement Therapy.

Fluoride

Well known for its ability to prevent cavities, fluoride also has an effect on bone metabolism. Treatment with large doses, such as 30 mg/day, has been shown to increase bone mass in individuals with osteoporosis. However, the new bone growth may not necessarily be high-quality bone, and those treated with fluoride sometimes show evidence of abnormalities in their bone tissue. Conflicting studies also show an increased incidence of fractures in people receiving fluoride. Side effects include anemia, gastrointestinal symptoms, arthritis, and vomiting.

Hormone Replacement Therapy (HRT)

Until recently, Hormone Replacement Therapy was the primary choice for building bone density, along with treating menopausal symptoms. The standard recommendation given women by their doctors was to exercise, consume large quantities of calcium, and begin estrogen replacement. Yet while a fall in estrogens (and progesterone and testosterone) can cause bones to become thinner, a rise in estrogen alone won't reverse this process.

Estrogen replacement helps to slow or stop the osteoporotic process by slowing the resorption of bone cells. However, it does not make bones any stronger since estrogen does not stimulate the growth of new bone cells. Possible side effects include breast tenderness, headaches, leg cramps, gallstones, worsened uterine fibroids and endometriosis, vaginal bleeding, high blood pressure, blood clots, nausea and vomiting, fluid retention, impaired glucose tolerance, and increased risk of endometrial cancer and breast cancer.

The Women's Health Initiative (WHI) conducted a study of 16,608 women who took a combination of synthetic estrogen and progestin or a placebo over a period of five years. The researchers found that the risks of hormone replacement therapy far outweighed the benefits of decreased risk of hip fracture and colorectal cancer. The study was halted three years short of its original completion date in 2005 due to findings of increased risk for heart disease, heart attacks, strokes, and breast cancer.

Whether lower levels of hormones even cause osteoporosis-related fractures is still debatable. If estrogen deficiency is the cause, one would expect women with the disease to have lower levels of estrogen than women without the disease. However, studies have found that estrogen levels are similar in postmenopausal women with and without osteoporosis.