Bone Density Scanning - DEXA

Bone Density Scanning - DEXA

In the United States, more than 40 million people either already have osteoporosis or are at high risk due to low bone mass. Osteoporosis can occur in both men and women and at any age, but it is most common in older women.
What Causes Osteoporosis?

Many risk factors can lead to bone loss and osteoporosis. Some of these things you cannot change and others you can. Risk factors you cannot change include:

  • Gender. Women get osteoporosis more often than men.
  • Age. The older you are, the greater your risk of osteoporosis.
  • Body size. Small, thin women are at greater risk.
  • Ethnicity. White and Asian women are at highest risk. Black and Hispanic women have a lower risk.
  • Family history. Osteoporosis tends to run in families. If a family member has osteoporosis or breaks a bone, there is a greater chance that you will too.

Other risk factors are:

  • Sex hormones. Low estrogen levels due to missing menstrual periods or to menopause can cause osteoporosis in women. Low testosterone levels can bring on osteoporosis in men.
  • Anorexia nervosa. This eating disorder can lead to osteoporosis.
  • Calcium and vitamin D intake. A diet low in calcium and vitamin D makes you more prone to bone loss.
  • Medication use. Some medicines increase the risk of osteoporosis.
  • Activity level. Lack of exercise or long-term bed rest can cause weak bones.
  • Smoking. Cigarettes are bad for bones, and the heart, and lungs, too.
  • Drinking alcohol. Too much alcohol can cause bone loss and broken bones.

Can Osteoporosis Be Prevented?

There are many steps you can take to help keep your bones healthy. To help keep your bones strong and slow down bone loss, you can:

  • Eat a diet rich in calcium and vitamin D
  • Exercise
  • Not drink in excess or smoke.


A healthy diet with enough calcium and vitamin D helps make your bones strong. Many people get less than half the calcium they need. Good sources of calcium are:

  • Low-fat milk, yogurt, and cheese
  • Foods with added calcium such as orange juice, cereals, and breads.

Vitamin D is also needed for strong bones. Some people may need to take vitamin D pills. The chart on this page shows the amount of calcium and vitamin D you should get each day.

Recommended Calcium and Vitamin D Intakes


Life-stage group Calcium mg/day Vitamin D (IU/day)
Infants 0 to 6 months 200 400
Infants 6 to 12 months 260 400
1 to 3 years old 700 600
4 to 8 years old 1000 600
9 to 13 years old 1300 600
14 to 18 years old 1300 600
19 to 30 years old 1000 600
31 to 50 years old 1000 600
51 to 70-year old males 1000 600
51 to 70-year old females 1200 600
>70-years old 1200 800
14 to 18 years old, pregnant/lactating 1300 600
19 to 50 years old, pregnant/lactating 100 600


Definitions: mg = milligrams; IU = International Units Source: Food and Nutrition Board, Institute of Medicine, National Academy of Sciences, 2010.


Exercise helps your bones grow stronger. To increase bone strength, you can:

  • Walk
  • Hike
  • Jog
  • Climb stairs
  • Lift weights
  • Play tennis
  • Dance

Healthy Lifestyle

Smoking is bad for bones as well as the heart and lungs. Also, people who drink a lot of alcohol are more prone to bone loss and broken bones due to poor diet and risk of falling.

What Are the Symptoms of Osteoporosis?

Osteoporosis is called the "silent disease" because bone is lost with no signs. You may not know that you have osteoporosis until a strain, bump, or fall causes a bone to break.

How Is Osteoporosis Diagnosed?

A bone mineral density test is the best way to check your bone health. This test can:

  • Diagnose osteoporosis and tell you whether you are likely to break a bone.
  • Check bone strength
  • See if treatments are making the bones stronger.

How Is Osteoporosis Treated?

Treatment for osteoporosis includes:

  • A balanced diet rich in calcium and vitamin D
  • An exercise plan
  • A healthy lifestyle
  • Medications, if needed.

How Can I Prevent Falls?

Men and women with osteoporosis need to take care not to fall down. Falls can break bones. Some reasons people fall are:

  • Poor vision
  • Poor balance
  • Certain diseases that affect how you walk
  • Some types of medicine, such as sleeping pills.

Some tips to help prevent falls outdoors are:

  • Use a cane or walker
  • Wear rubber-soled shoes so you don't slip
  • Walk on grass when sidewalks are slippery
  • In winter, put salt or kitty litter on icy sidewalks.

Some ways to help prevent falls indoors are:

  • Keep rooms free of clutter, especially on floors
  • Use plastic or carpet runners on slippery floors
  • Wear low-heeled shoes that provide good support
  • Do not walk in socks, stockings, or slippers
  • Be sure carpets and area rugs have skid-proof backs or are tacked to the floor
  • Be sure stairs are well lit and have rails on both sides
  • Put grab bars on bathroom walls near tub, shower, and toilet
  • Use a rubber bath mat in the shower or tub
  • Keep a flashlight next to your bed
  • Use a sturdy step stool with a handrail and wide steps
  • Add more lights in rooms
  • Buy a cordless phone to keep with you so that you don't have to rush to the phone when it rings and so that you can call for help if you fall.

DEXA (Dual-Energy X-ray Absorptiometry) is diagnostic procedure which is used to measure bone mineral density. A DEXA scan is a simple and non-invasive procedure. Measurements of the lower spine, hips and sometimes the wrist are taken. The procedure is painless and radiation exposure is very minimal. DEXA scans are recommended if you:

  • Over the age of 50 and have a FAMILY member with Osteoporosis.
  • Are a post-menopausal women and not taking hormone replacement therapy.
  • Small frame/bone structure
  • Have a history of smoking & / or alcohol use.
  • Have experienced bone loss or bone trauma.
  • Have a family history of osteoporosis, fracture(s), hyperthyroidism and other related clinical conditions such as diabetes, liver or kidney disease.
  • Use certain medication known to contribute to bone loss as a side effect such as corticosteroids, prednisone, dilantin, some barbiturates and thyroid replacement medications.


There is little or no preparation for a DEXA Scan. Eat as you normally do, however do not take any calcium supplements 24 hours prior to the exam. Dress comfortably and try to avoid garments with metal (zippers, belts, or buttons). You may have to wait 10-14 days before undergoing a DEXA test if you have had another diagnostic study which required the use of a contrast agent such as barium enema, an upper/lower GI series esophagram; or have been injected with a contrast material for a computed tomography (CT) scan or radioisotope scan for a bone or PET/CT scan. As with all radiological procedures patients should inform the technologist if there is any chance of pregnancy.

How is a DEXA scan performed?

You will be asked to lie on the examination table for a short time while the arm of the machine passes over your body taking measurements. It is important that you stay as still as possible during the procedure to ensure a clear, useful image. Dr. DaSouza interprets the results of the DEXA Scan and provides a report to your primary care provider or gynecologist. In addition to other aspects of your study found in the interpretation, Your test results will include two scores - T score and a score:
T score  - indicates the amount of bone you have when compared with a young adult of the same gender with peak bone mass. A score above -1 is considered normal. A score between -1 and -2.5 is classified as osteopenia, the first stage of bone loss. A score below -2.5 is defined as osteoporosis. It is used to estimate your risk of developing a fracture. 
Z score - indicates the amount of bone you have when compared to other people in your age group and of the same size and gender. If it is unusually high or low, it may indicate a need for further medical tests.