Updated June 09, 2015.

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Definition:

Osteopenia is a condition where your bone density is below normal, but not yet considered osteoporosis.

Bone density is typically measured with a DEXA scan. DEXA stands for "dual-energy x-ray absorptiometry," and is considered the most accurate test for bone density.

The results of a DEXA scan are reported in two ways: as T-scores and as Z-scores. A T-score compares your bone density to the optimal peak bone density for your gender.

It is reported as number of standard deviations below the average. A T-score of greater than minus-1 is considered normal. A T-score of minus-1 to minus-2.5 is considered osteopenia, and a risk factor for developing osteoporosis. A T-score of less than minus-2.5 is diagnostic of osteoporosis.

It is critical to know when an individual has osteopenia, as preventing the progression to osteoporosis is important. The concern is that as bone becomes less dense, there is an increased susceptibility to fracture. Treatment of osteopenia may be accomplished with diet modifications, supplements, or medications.