A bone density number is not a verdict. It is a starting point for habits that help at any age. Bone mass, also known as bone mineral density, measures the amount of mineral (mainly calcium and phosphorus) in a given volume of bone. A bone density test gives a helpful look at the health of your skeleton and your future risk of fractures and osteoporosis. Here's what a healthy bone mass is, who should be tested, and what your results mean.

How is Bone Mineral Density Tested?

The clinical test to reveal your T-score is called a dual-energy x-ray absorptiometry. The experience is pain-free and similar to having a regular x-ray. 

There are two varieties of bone mass tests:

1. Central DXA test. This is the most common test for bone density. It measures your bone density at the hip or lower spine.

2. Peripheral DXA test. This assessment measures your bone density from your finger, wrist, heel, or forearm. Often, doctors will order a peripheral DXA test for screening before following up with a central DXA test if deemed necessary. 

What is a Healthy Bone Mass?

Your BMD test results will be delivered as a T-score. The test compares your bone mineral density to the skeletal system of a young, healthy person. Your T-score is an indication of how you compare to the mean. For example, a T-score of 0 is considered normal and healthy. There is little variation between your bones and the bone density of a healthy young adult. 

T-scores lower than 0 indicate lower bone mineral density. The farther from 0 you get, the greater your risk of bone injury. 

A normal bone mineral density falls between -1 and +1. A T-score between -1 and -2.5 may result in a diagnosis of low bone mass.

What T-Score indicates Osteoporosis and Osteopenia?

Bone density testing is often used to diagnose osteoporosis. A T-score of -2.5 or lower is considered osteoporotic. Osteopenia is the step before osteoporosis when patients have a low bone density and a high risk of developing osteoporosis if it continues to drop. 

Can You Combat Osteopenia?

The good news is that a bone density test that finds osteopenia or low bone density offers an opportunity to make lifestyle changes that may lower the risk of osteoporosis.

For many people with osteopenia, doctors focus first on lifestyle changes to support bone density, and decide on medication case by case based on overall fracture risk. 1

Lifestyle Changes

The two primary strategies that doctors recommend to build bone density are:

• Exercise. Weight-bearing exercise, including lifting weights, walking and jogging, can improve bone mineral density. In the LIFTMOR trial, supervised high-intensity resistance and impact training improved bone mineral density in postmenopausal women with low bone mass. 2

• Diet. A diet rich in bone-building nutrients like calcium and vitamin D supports strong bones. The Framingham Osteoporosis Study of over 5,000 adults highlighted the importance of getting enough calcium and magnesium for bone health. 3

Depending on other health factors, reaching a healthy weight, quitting smoking and other healthy lifestyle changes can also help lower your chances of developing osteoporosis.

Whether you have a low bone density or it runs in your family, it’s never too early to set yourself up for healthy bones. Engaging in regular weight-bearing exercise and rounding out your diet are two of the most important things you can do to build strong bones. 

If you or your family members find it hard to get enough calcium and magnesium from food alone, ask your doctor whether a supplement makes sense.

Reference

¹ Eriksen EF. Treatment of osteopenia. Rev Endocr Metab Disord. 2012;13(3):209-223. doi:10.1007/s11154-011-9187-z

² Watson SL, et al. High-Intensity Resistance and Impact Training Improves Bone Mineral Density and Physical Function in Postmenopausal Women With Osteopenia and Osteoporosis: The LIFTMOR Randomized Controlled Trial. J Bone Miner Res. 2018;33(2):211-220. doi:10.1002/jbmr.3284

³ Sahni S, Mangano KM, McLean RR, Hannan MT, Kiel DP. Dietary Approaches for Bone Health: Lessons from the Framingham Osteoporosis Study. Curr Osteoporos Rep. 2015;13(4):245-255. doi:10.1007/s11914-015-0272-1

Sources

1. Watson SL, et al. High-intensity resistance and impact training improves bone mineral density and physical function in postmenopausal women with osteopenia and osteoporosis: the LIFTMOR randomized controlled trial. J Bone Miner Res. 2018;33(2):211-220. doi:10.1002/jbmr.3284. doi.org/10.1002/jbmr.3284
2. US Preventive Services Task Force. Screening for osteoporosis to prevent fractures: US Preventive Services Task Force recommendation statement. JAMA. 2018;319(24):2521-2531. doi:10.1001/jama.2018.7498. doi.org/10.1001/jama.2018.7498