Areal bone mineral density values have been shown to predict the risk of osteoporotic fracture. The World Health Organization (WHO) has established criterion for the diagnosis of osteoporosis. A T-score is used. It is defined as the number of standard deviations above or below the average aBMD for young healthy white women (2).

2. Osteoporosis: Prevention, Diagnosis, and Therapy. (2000). NIH Consensus Statement on-line 2000 March 27-29;17:1-36.

http://consensus.nih.gov/cons/111/111_intro.htm