Osteoporosis

Not long ago osteoporosis was considered a disease of little old ladies and a "normal" part of aging. Now we know that it is really a disease of young women, even young girls.

Study of bone metabolism, improved diagnostic tests, new therapeutic options - all these changed the old notions and hopefully will lead to improved prevention and treatment of this potentially deadly condition.

Definition

Osteoporosis - literally "porous bones" is defined as a "disease of decreased bone density and deterioration of the skeleton with increased fragility" that puts you at a higher risk of fracture. Since "low bone mass" is not a very exact definition and certainly not clinically useful, a new definition was developed based on the measurement of Bone Mineral Density (BMD).

Healthy women between ages 20 and 40 are said to have the lowest risk of fracture because they have the highest BMD. Their relative risk is arbitrarily set at 1. As BMD decreases the risk of fracture goes up. For each standard deviation (SD) decrease of BMD the risk of fracture doubles. Standard deviation is a mathematical tool used in statistical calculations.

Patients whose BMD is 1 SD lower than that of young healthy women have double the risk of fracture. If it's 2 SD lower, the risk increases to 4. With this in mind, a new definition is:

• Normal - BMD less than or equal to 1 SD below peak bone mass (healthy young women).
• Low bone mass (osteopenia) - 1 SD to 2.5 SD below peak bone mass.
• Osteoporosis - more than 2.5 SD below peak bone mass.

Most physicians feel that a woman should not wait until her bones lose enough mass to be 2.5 SD below and treatment should begin somewhere around 2 SD or earlier.

Bone mass

Bone mass increases from childhood to about the age 35, where it peaks and gradually begins to diminish, causing bones to become less dense. An average bone loss before menopause is 1-1.25% a year, but it accelerates to 3-4% after the menopause. About half of bone mass is lost before menopause.

Known risk factors of low bone density include:

• being a female
• petite body frame
• Caucasian or Asian race
• sedentary life style
• women who never had children
• post-menopausal
• low calcium intake
• smoking
• excessive ingestion of caffeine
• high dietary sodium which promotes calcium loss in the urine
• excessive alcohol consumption

In addition, the use of certain medications (corticosteroids, Dilantin, Heparin, Coumadine, chemotherapeutic agents) decreases bone mass.

Deficiency of estrogen, progesterone, testosterone, growth hormone and vitamin D also reduce bone density. Genetic factors also play a major role.

How common is osteoporosis?

A recent National Health and Nutrition Examination Survey (NHANES III, 1988-1994) showed that according to the definition above up to 18% of women over 50 had osteoporosis and up to 50% had low bone mass (osteopenia). This translates into 4-6 million US women suffering from osteoporosis and 13-17 million with low bone mass. In men over 50 the numbers were a little better - 1-2 million with osteoporosis and 4-9 million with low bone mass.

Since low bone mass is defined as 1SD to 2.5 SD below normal, it means 2 to 5 times higher risk of fracture, which means that almost 34 million women and men over 50 are at increased risk of fracture.

The annual incidence of osteoporotic fractures is about 1.5 million (700,000 vertebral fractures; 250,000 fractures of the wrist; 250,000 hip fractures; and 300,000 fractures of other bones).

Fractures are more prevalent in whites than in blacks and in women than in men. The female-to-male fracture ratios are 7:1 for vertebral fractures; 1.5:1 for wrist fractures; and 2:1 for hip fractures.

Cost of osteoporosis

The estimated medical cost of fractures in 1995 was a staggering $13.8 billion. But there is another cost as well - human lives. Hip fractures, the most common type of osteoporotic fracture, are associated with a 20% increase in death rate. Increased mortality remains high for several years after a fracture.

But even if you survive a hip fracture, you are not home free. Over half of patients require nursing home care after release from the hospital and 79% remain there a year later.

The symptoms

Osteoporosis is often called the "silent epidemic" because gradual bone loss may not be associated with any symptoms until a fracture develops. The only "early" symptom may be back pain associated with activity, aggravated by long periods of sitting or standing, and relieved by rest. This pain is due to micro-fractures.

Unfortunately, most women and men realize they suffer from osteoporosis only when a fracture occurs. Common fracture sites include the vertebrae, the wrist and the hip.

Vertebral fracture

Vertebral fracture, also known as compression fracture, usually happens in the middle or lower back. This causes pain that is usually intense and severe and lasts 2-3 weeks. It decreases over the next 3-4 month and can either disappear completely or turn into chronic pain.

Unfortunately, once a vertebral fracture has occurred, the risk for further fractures becomes much higher. Multiple vertebral compression fractures can lead to loss of height.

Hip fractures

Hip fractures are the most serious complication of osteoporosis. In the first 12 months following a hip fracture, the mortality rate may be as high as 20%. Up to 50% of patients will be unable to walk or perform activities of daily living without assistance and 25% will require long-term care.

Diagnostic tests

A "regular" X ray may show osteoporosis but only after 30% to 40% of bone mass is already lost. Two techniques have been developed for early diagnosis of osteoporosis.

Dual-energy x-ray absorptiometry (DEXA) allows measurement of the spine and hips, the sites most prone to bone loss and fractures. Unfortunately, DEXA machines are rather large and only available in large medical centers.

Quantitative ultrasound can measure bone density in wrists and heels. The results have good correlation with the risk of hip or vertebral fracture and the equipment is smaller and can be used at a doctor's office.

Interpreting the results

Most methods of BMD measurement provide three numbers - bone density, T score and Z score.

Bone density is expressed in grams per square centimeter (gm/cm²).

The T score is the number of SDs below the peak bone mass, that of a healthy 30 year old. The T score of -2 means that you are 2 SDs below peak and you are 4 times more likely to experience a fracture than a healthy young woman.

The Z score compares you with a normal age-matched and sex-matched control. A 70 year old woman with a Z score of -1 is 1 SD below the normal 70 year old woman.

Preventing osteoporosis

Calcium

Calcium intake decreases significantly after childhood in most Americans. This is unfortunate, since even most children don't get enough calcium in their diet. Since bone mass increases until the age of 30-35, it is essential to supply enough calcium during the period of growth. Many doctors call osteoporosis a pediatric disease because childhood is the time we can do the most to affect peak bone mass.

However, it's never too late to improve your calcium intake. Most pre-menopausal adult women should get at least 1,000 mg a day. Postmenopausal women not on hormone replacement should get even more, about 1,500 mg.

Milk has been touted as the best source of calcium, but actually it is not. A glass of milk contains about 300 mg of calcium but it is not well absorbed. The best dietary sources of calcium are green leafy vegetables, grains and some others. You will find more information about excellent sources of calcium in the vitamin section of NYDocs.

Many calcium supplements are available. Some of the best known are calcium citrate (Citrical), calcium carbonate and calcium from oyster shells. The best type of calcium supplement is microcrystalline hydroxiapatite concentrate (MCHC).

Studies have shown that taking MCHC can increase bone density by up to 6.1 per cent, even in cases of advanced bone loss. It also improves healing of fractures and relieves back pain in women suffering from bone loss.

MCHC is so effective because it is a specially processed whole bone concentrate, derived from young calf bone. It provides highly absorbable calcium and other important minerals needed to build strong bones. Besides calcium, it also contains phosphate, protein and trace amounts of magnesium, fluoride and 25 other minerals that are naturally present in a healthy bone.

Lifestyle changes

To decrease the risk of osteoporosis you should:

Stop smoking

Avoid excessive alcohol intake

Participate in weight-bearing exercises at least 3 times a week

Reduce caffeine intake

Treatment of osteoporosis

Hormone replacement therapy

Estrogen and progesterone supplementation have been a mainstay in prevention and treatment of osteoporosis in postmenopausal women. However, there is a right way and a wrong way to provide hormone replacement. To learn more, please see the October issue of Health Pearls newsletter devoted to this subject.

Other hormones necessary for bone health are testosterone and growth hormone. Both of these decrease after the age of 40 and should be corrected. For more information about testosterone and growth hormone, please see the August issue of Health Pearls newsletter.

Medications

Fosamax (Alendronate) is used for both prevention and treatment. The usual dose is 5 to 10 mg a day. Side effects include esophagitis and occasional esophageal hemorrhage.

Didronel (Etidronate) is approved for Paget's disease but is often used for treatment of osteoporosis and is less expensive than Fosamax.

Evista (Raloxifene) is a selective estrogen-receptor modulator that was recently approved for prevention of osteoporosis. The usual dose is 60 mg a day. Studies showed that it prevents bone loss in the spine and hips but the effect is not as powerful as with estrogen replacement or with Fosamax. Side effects include hot flashes and increased risk of deep vein thrombosis, a potentially fatal complication.

Miacalcin (Calcitonin-salmon) is used as a nasal spray. It does increase bone mass by 2-3% but does not appear to reduce the incidence of fractures.

Natural supplements

Besides calcium many other nutrients are required for bone health. They are:

Silicon, a mineral vital for normal growth and development of bones, hair, nails, skin, cartilage and connective tissue. The best source of organic silicon is Horstail silica, an herb used since ancient times to improve the health of the bones, nails and hair.

Vitamin K, essential for formation of osteocalcin, a special protein found only in bone. This protein serves as a matrix upon which calcium forms crystals – a process of bone formation.

Vitamin D facilitates absorption of calcium from the intestine and should be supplemented.

Magnesium activates an enzyme responsible for forming new calcium crystals in the bone. It is also required for activation of vitamin D.

Boron participates in bone formation and decreases bone loss.

Copper strengthens connective tissue and collagen and inhibits bone loss.

Ipriflavone is an isoflavone similar to natural substances found in wild yam and soybeans. It was first introduced in Japan in 1988. Ipriflavone has a structure similar to estrogen which probably explains its positive effect on bone mass. But unlike "real" estrogens, it does not stimulate breast or uterine tissue growth. Ipriflavone also activates bone-building cells called osteoblasts and inhibit osteoclasts - cells that break down bone.

Conclusion

Osteoporosis is serious and potentially fatal condition. It affects both women and men and begins much earlier in life than we realized.

Fortunately, it can now be detected much sooner using new diagnostic techniques which allows us a shot at prevention. Bone mass loss can be arrested or even reversed with some or all of the methods outlined above.

No matter how young or old your are, please start paying attention to your bones. It's never too early or too late to make your bones stronger.

Return to main menu