What exactly is osteopenia? How is it different from osteoporosis?

Jean

Osteopenia refers to decreased calcification or density of bone. Having osteopenia places a person at risk for developing osteoporosis, a more serious condition that causes bones to become brittle and possibly break. Bone density is described in relationship to what it should be in young women; it is expressed as a standard deviation from the mean (average) bone density in a 35-year-old. Within 1 standard deviation of the mean in either direction is considered normal. A bone density within the range of 1 to 2.5 standard deviations below the mean is defined as osteopenia, and greater than 2.5 standard deviations below the mean is osteoporosis.

The thinning of the bones that occurs with osteoporosis increases the risk of fractures. Hip fractures, in particular, can be quite devastating in elderly women. In the United States alone, the cost -- both direct (hospitalization, surgery, doctor's visits) and indirect (lost time from work) -- from fractures exceeds $7 *billion* annually!

Risk factors for osteopenia and osteoporosis include genetic predisposition, sedentary lifestyle, low dietary intake of calcium and vitamin D, petite stature and small bone structure, long-term use of steroids or heparin, cigarette smoking, and declining levels of estrogen after menopause. Some of these factors -- like genes and bone structure -- are things you are stuck with, but many of these risk factors are easy to modify. Doing regular weight-bearing exercise throughout life, ensuring adequate calcium intake and avoiding smoking are ways not only to improve bone health, but health in general. After menopause, bone loss becomes much more rapid; hormone replacement can slow or stop this loss.

If your history suggests you may be a risk for osteoporosis and you are nearing menopause, then a bone density test is a good idea. If the test indicates you already have osteopenia, which precedes osteoporosis, you may take steps to slow additional bone loss. The results may help you make a decision about starting estrogen after menopause. Estrogen is still the best preventive measure, although newer drugs like Evista and Fosamax provide an alternative.

Osteopenia is a warning -- time to sit up (actually, time to walk around the block and lift some weights!) and take measures to prevent developing osteoporosis.