What Do T-Scores Mean?

When you have a bone mineral density test for osteopenia or osteoporosis, the results are given to you in a number called a T-score. The T-score is a comparison of your bone density to a healthy 30-year-old adult, the stage at which the average adult has her greatest amount of bone density. The World Health Organization (WHO) developed and issued the T-score grading system in 1994. It is now used worldwide.

Significance

• The bone mineral density test to ascertain the T-score is most often given to postmenopausal women and men age 50 and older. The National Osteoporosis Foundation does not recommend routine bone mineral density testing for children, adolescents, healthy young men or pre-menopausal women. The bone mineral test to measure bone density at the hip and spine is usually done using a central DXA machine.

Normal Scores

• A T-score between +1 and -1 is normal for a healthy 30-year-old.

  If your T-score is between +1 and -1, your bone density is similar to the bone density of a healthy 30-year-old. The T-score is a measurement of the bone density in your hip and spine, so it does not necessarily mean that you do not have low bone mass in other parts of your body.

Osteopenia

• If your T-score is between -1.0 and -2.5, the bone density in your hip and spine is below normal and you have low bone density, or osteopenia. You should speak with your physician about options to promote and maintain bone health. If your T-score is closer to -2.5, you might want to discuss treatment related to osteoporosis, especially if you have had a recent bone fracture or fractures.

Osteoporosis

• If your T-score is below -2.5, it means that your have osteoporosis, a condition that causes bones to become weak and fracture. The lower the score, the lower your bone mass and the greater your risk of fracture. Speak with your physician about treatment, including medications and low-impact exercise interventions.

  Osteoporosis also can be diagnosed if you have a history of fractures without trauma. In the October 2009 issue of the "Journal of Endocrinological Investigation," Ranuccio Nuti and fellow researchers at the University of Siena point out that a large number of fractures occur in subjects with T-scores above -2.5 and that bone density is just one of the factors contributing to bone strength. The authors suggest that the presence of two or more fragility fractures should be considered as severe osteoporosis, independent of the T-score.

Frequency of Testing

• According to the National Osteoporosis Foundation, those taking an osteoporosis medication should have a bone mineral test by central DXA done every two years. Some medical professionals might recommend repeating the test after one year.