What is osteoporosis?
Osteoporosis is a disease that affects over 25 million people in the United States and is responsible for over 1.3 million fractures (broken bones) per year. It is characterized by low bone mass and deterioration of both the inner (trabecular) and outer (cortical) parts of bone, which can lead to bone fragility and fractures.

Osteoporosis is classified as either primary or secondary. Primary osteoporosis is subdivided into Type I (postmenopausal) and Type II (age-related). Most cases are primary Type I, affecting up to 80% of the women in the United States between the ages of 50 and 70. Primary Type II osteoporosis affects nearly half of all people over the age of 75, and it affects women only slightly more than men.

Secondary osteoporosis can occur as a side effect from the use of certain drugs, such as corticosteroids and heparin. Some diseases, such as rheumatoid arthritis, kidney disease, and some forms of cancer, can also lead to secondary osteoporosis.

Who is at risk?
Most risk factors are attributed to genetics. Women are affected more than men, especially Caucasian and Asian women who are thin and who have a family history of osteoporosis.

Certain lifestyle factors can also lead to the development of osteoporosis. These include smoking, excessive consumption of alcohol and caffeine, low calcium intake, and little or no physical exercise.

Measuring bone mass
Measuring bone mass of the spine or hip gives a good indication of the body's overall bone health. X-rays are not a reliable way to assess bone mass. The most recent technology in bone mass density measurement uses dual-energy x-ray absorptiometry (DEXA) (see photo). Although it is more expensive, there is significantly less radiation exposure than with x-rays.

Secondary problems
Bone structures that are composed of trabecular bone, such as the hip and spine, are the most common sites of osteoporotic fractures. These fractures can occur as a result of a traumatic (forceful) injury, such as a fall. However, if bones are weakened enough from osteoporosis, fractures can occur with little or no trauma, such as lifting a light box.

Spinal complications result from compression of the vertebrae (bones of the spinal column). As a result, a patient might experience a loss in height and postural deformities, such as a dowager's hump (curvature of the spine).

Other secondary problems can include gastrointestinal (digestive) disorders and bone marrow and connective tissue diseases.

But I'm young, and I don't have to worry about osteoporosis, or do I?
Young, white women, especially athletes, who may be predisposed to inadequate peak bone mass can be at increased risk of developing osteoporosis. Vigorous athletic training, eating disorders, and poor dietary habits can all contribute to low total-body fat percentage. A certain level of body fat percentage is needed to produce sex hormones, especially estrogen. Thus, when the body is low in fat, the production of estrogen is reduced, which in turn accelerates the loss of bone mass.

The importance of early diagnosis
The loss of bone mass spans many years over a person's lifetime. Unfortunately, osteoporosis is usually symptomless and not detected until a fracture has occurred. That's why early diganosis is important. It allows one to change any lifestyle habits that can lead to osteoporosis and take the necessary steps to prevent fractures and slow down the progression of osteoporosis.

Steven C. Mares, M.D.
Williamsburg, Virginia