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Bone Scans and Bone Health Screenings

When should you get a bone density scan, and why?

DEXA Bone Scans: What Your T-Score Means

Being told your bones are thin is cause for concern, but not alarm. If your T-score is low, what can you expect?

First of all, unless you're a woman past menopause or a man older than 50, your risk of fracture is very low. In these groups, even with a T-score less than -2.5, bones are usually strong and treatment isn't recommended.

On the other hand, if you've been told you have osteoporosis, take it seriously. Feeling fine is no protection at all: fractures of the spine can be silent and painless. "Anyone with osteoporosis should be on some kind of treatment," according to Baker.

For those with osteopenia (T-score between -1.0 and -2.5), the picture gets confusing. It's harder to predict fracture risk in this group of people. Focusing too closely on the T-score can be a mistake. "The DEXA T-score is not a perfect predictor for bone health or fracture risk," says Rhee.

Actually, bone density (measured by T-score) is only one aspect of fracture risk. Your risk factors (see above) can be just as important. Using both the T-score and risk factors for fracture leads to better predictions.

The World Health Organization is developing a formula using risk factors in combination with the T-score to determine 10-year fracture risk. "We'll probably see this coming into use in the next few years," says Rhee.

Bone Scan T-Scores: When It's Time to Treat

The National Osteoporosis Foundation recommends treatment for:

  • Postmenopausal women with T-scores less than -2.0, regardless of risk factors.
  • Postmenopausal women with T-scores less than -1.5, with osteoporosis risk factors present.

In addition, anyone with a fragility fracture (a fracture from a minor injury) should be treated for osteoporosis. This is true regardless of the DEXA scan results.

Treatment generally begins with a bisphosphonate medicine (Actonel, Fosamax, Boniva, or Reclast). These drugs are proven to increase bone density and reduce the risk of fracture. Other options include:

  • Estrogens (hormone replacement therapy)
  • Calcitonin
  • Teriparatide
  • Raloxifene

In addition, the National Osteoporosis Foundation recommends 1,200 milligrams of daily calcium intake -- through diet and/or supplements.

When Should You Get a Bone Density Scan?

When, and how often, you should get a bone density scan depends on your age, risk factors, and whether you’ve already been diagnosed with thinning bones.

The general rule: anyone at risk for osteoporosis should get a bone density scan. Don’t wait for a fracture or a formal diagnosis.

Postmenopausal women are at highest risk, because estrogen (which falls after menopause) preserves bone strength.  But men get osteoporosis, too. "They just get it later," says Mary Zoe Baker, MD, an endocrinologist and professor of medicine at the University of Oklahoma Health Sciences Center. Usually around age 70, "men start to catch up to women" in developing osteoporosis, according to Baker.

Next Article:

Osteoporosis Glossary

  • Bone Mineral Density - A measurement of the amount of calcium and minerals in bone tissue.
  • Calcium - A mineral in (and vital to) your bones. If your body lacks calcium, it takes it from bones.
  • DEXA (dual energy X-ray absorptiometry) - a test used to measure bone mineral density.
  • Osteoporosis - A decrease in bone density, which increase the risk of fractures.
  • Vitamin D - A vitamin that helps your body absorb calcium.
  • View All Terms

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