OsteoporosisGeneral Description
Osteoporosis is a skeletal disorder characterized by compromised bone strength and an increased risk of fractures, especially of the hip, spine, and wrist. It is estimated that 10 million people in the U.S. have osteoporosis and an additional 18 million have low bone mass, placing them at increased risk for the disease.¹ Although it is the underlying cause of most fractures in older people, in most cases osteoporosis remains undetected until a fracture occurs. In the U.S., osteoporosis is responsible for more than 1.5 million fractures annually, including approximately 300,000 hip fractures, 700,000 vertebral fractures, 250,000 wrist fractures, and more than 300,000 fractures at other sites.¹ While the disease is most commonly seen in post-menopausal white and Asian women, osteoporosis occurs in all ethnic and gender groups. Once considered to be a natural part of aging, osteoporosis is now recognized as a largely preventable disease.

Contributing factors
Bone strength is a reflection of two main features: bone density and bone quality. Bone density is expressed as grams of mineral per volume and is determined by peak bone mass and amount of bone loss. Bone quality refers to architecture, turnover, damage accumulation (e.g., microfractures) and mineralization. Currently there is no accurate measure of overall bone strength. Bone mineral density (BMD), which accounts for approximately 70 percent of bone strength, is frequently used as a proxy measure. Osteoporosis is diagnosed when BMD measurements are markedly below the average for healthy young adults. This often results from accelerated bone loss associated with aging, but may also occur without accelerated bone loss in individuals who do not achieve optimal bone mass during childhood and adolescence. Thus, sub-optimal bone growth in childhood is as important as bone loss to the development of osteoporosis.² Optimization of bone health is a process that must occur throughout one's lifetime. Factors that influence bone health at all ages are essential to the prevention of osteoporosis.

Osteoporosis is characterized as primary or secondary. Primary osteoporosis can occur in both genders at all ages, but is most often seen in post-menopausal women and elderly men. Secondary osteoporosis is caused by medication side effects or other diseases or conditions such as alcoholism, genetic disorders, gastrointestinal diseases, endocrine disorders, connective tissue diseases, hypogonadism, and nutritional deficiencies.² These secondary causes can aggravate primary osteoporosis.

The development of primary osteoporosis is often associated with aging, largely because of the role hormones play in bone preservation. The female hormone estrogen helps protect bones against mineral loss. After menopause, women's estrogen levels decline drastically, which can lead to bone loss and osteoporosis. Men have less risk of developing osteoporosis because they do not experience the same kinds of hormone losses as women. Because of this, osteoporosis does not normally affect men until they reach advanced age.

Conventional treatment
Treatment of osteoporosis aims to stop bone loss and prevent falls. Falls often cause the bone fractures that typify osteoporosis. Many doctors prescribe hormone replacement therapy (HRT) to restore declining hormone levels and slow the rate of bone loss. However, the long-term safety of HRT is not yet known. The naturally occurring hormone calcitonin can increase bone density in the spine and reduce the pain of fractures.³ The prescription drug alendronate (Fosamax¬) helps maintain bone mass in postmenopausal women by inhibiting the activity of cells that draw calcium out of bone tissues.^4,5

Nutritional/lifestyle considerations
Osteoporosis is viewed as a preventable disease, with diet and exercise as the primary interventions. Because bones are composed mostly of calcium, a calcium-rich diet, or supplemental calcium, is important for all people at risk for osteoporosis. These people should also be sure they have adequate vitamin D, a nutrient the body needs in order to absorb calcium. Because peak bone density is established during childhood and adolescence, intake of calcium and vitamin D during these years is important for reducing the risk of osteoporosis later in life. Several other minerals such as magnesium, zinc, copper, boron, and silica along with vitamin K, also contribute to bone formation. A combination of healthy diet and exercise is the best way to prevent osteoporosis. Exercise builds bone strength and helps prevent bone loss. Weight-bearing exercises such as walking, jogging, or playing tennis, done on a regular basis, are best for preventing osteoporosis.³