Bone Mass Measurement: What the Numbers Mean:
*What is a bone density test?
A bone mineral density (BMD) test can provide can provide a snapshot of your bone health. The test can identify osteoporosis, determine your risk for fractures (broken bones) and measure your response to osteoporosis treatment. The most commonly used BMD test is called a central dual-energy x-ray absorptiometry or central DXA test. It is painless-a bit like having an x-ray. The test can measure bone density at your hip and lumbar spine.
Peripheral bone density tests measure bone density in the lower arm, wrist, finger or heel. These tests are often used for screening purposed and can help identify people who might benefit from follow-up bone density testing at the hip and lumbar spine.
What does the test do?
A BMD test measures your bone mineral density and compares it to that of an established norm or standard to give you a score. Although no bone density test is 100 percent accurate, the test is an important predictor of whether a person will have a fracture in the future.
The T Score:
Most commonly, your BMD test results are compared to the bone mineral density of a healthy young adult and you are given a T-score. A score of 0 means your BMD is equal to the norm for a healthy young adult. Differences between your BMD and that of the healthy young adult norm are measured in units called standard deviations (SD’s). The more standard deviations below 0, indicated as negative numbers, the lower your BMD and the higher your risk of fracture.
As shown in the table on page 2, a T-score between plus one and -1 is considered normal or healthy. A T-score between -1 and -2.5 indicates that you have low bone mass, although not with osteoporosis. A T-score of -2.5 or lower indicates that you have osteoporosis. The greater the negative number, the more severe the osteoporosis.
Low bone mass versus osteoporosis:
The information provided by a BMD test can help your doctor decide which prevention or treatment options are right for you.
The World Health Organization definitions based on bone density levels:
Normal: Bone density is within 1 SD (*1 or-1) of the young adult mean
Low bone mass: Bone density is between 1 and 2.5 SD below the young adult mean (-1 to -2.5 SD)
Osteoporosis: Bone density is 2.5 SD or more below the young adult mean (-2.5 SD or lower)
If you have low bone mass that is not low enough to be diagnosed as osteoporosis, this is sometimes referred to as osteopenia. Low bone mass can be caused by many factors such as:
*Low body weight
*A medical condition or medication to treat such a condition that negatively affects bone.
Although not everyone who has low bone mass will develop osteoporosis, low bone mass is an important risk factor for osteoporosis and fractures.
As a person with low bone mass, you can take steps to help slow down your bone loss and prevent osteoporosis in your future. Your doctor will want you to develop or keep healthy habits such as eating foods rich in calcium and vitamin D and doing weight-bearing exercise such as walking, jogging or dancing. In some cases, your doctor may recommend medication to prevent osteoporosis.
Osteoporosis. If you are diagnosed with osteoporosis, these healthy habits will help but your doctor will probably also recommend that you take medication. Several effective medication are available to slow or even reverse bone loss. If you do take medication to treat osteoporosis, your doctor can advise you concerning the need for future BMD tests to check your progress.
Who should get a bone density test?
The U. S. Preventive Services Task Force recommends that all women age 65 and older should have a bone density test. Postmenopausal women who are younger than age 65 and at increased risk of osteoporosis as determined by a formal clinical risk assessment tool should also have a BMD test.
Due to a lack of available evidence, the Task Force did not make recommendations regarding osteoporosis screening in men.
For more information on osteoporosis, contact the: NIH Osteoporosis and Related Bone Diseases National Resource Center.
If you need more information about available resources in your language or another language, please visit our website or contact the NIH Osteoporosis and Related Bone Diseases-National Resource Center.
For your information:
This publication contains information about medications used to treat the health condition discussed here. When this publication sheet was developed, we included the most up to date (accurate) information available. Occasionally, new information on medication is released.
For updates and for any question about any medications your are taking, please contact the U.S. Food and Drug Administration (FDA) toll free at 888-INFO-FDA (463-6332) or visit its website at https://www.fda.gov. For additional information on specific medications, visit Drugs@FDA at htts://www.acessdata.fda.gov/scripts/cder/daf. Drugs@FDA is a searchable catalog of FDA-approved drug products.
NIH Pub. No 18-7887-E
National Institute of Health
Osteoporosis and Related Bone Diseases-National Resource Center
2 AMS Circle
Bethesda, MD 20892-3676
Phone: (202) 223-0344
Toll Free- 800-624-BONE
TTY: (202) 466-4315
Fax: (202) 293-2356
Disclaimer: This information was taken directly from the NIH Osteoporosis pamphlet on Bone Mass Measurement and I give them full credit for the information. Please call the above numbers for more information.