Osteoporosis is a condition that occurs when a person experiences significant loss of bone density. This leads bones to becoming more fragile and prone to fracture. The word “osteoporosis” means “porous bone.”
The condition commonly affects older adults and can cause height loss over time.
Diagnosing osteoporosis typically requires several steps to make a definitive diagnosis. A doctor will thoroughly evaluate your risk for osteoporosis as well as fracture risk. Steps for diagnosing osteoporosis include the following.
Taking a Medical History
A doctor will ask questions related to osteoporosis risk factors. A family history of osteoporosis increases your risk. Lifestyle factors, including diet, physical activity, drinking habits, and smoking habits can also impact your risk. A doctor will also review medical conditions you have and medications you may have taken. Symptoms of osteoporosis that your doctor will likely ask you about include any bone fractures that occurred, a personal history of back pain, a loss of height over time, or a stooped posture.
Performing a Physical Exam
A doctor will measure a person’s height without shoes and compare this to previous measurements. Height loss can indicate osteoporosis. Your doctor may ask if you have difficulty rising from a sitting position without using your arms to push yourself up. They may also perform blood tests to evaluate your levels of vitamin D, as well as some other blood tests to determine the overall metabolic activity of your bones. Metabolic activity may be increased in the case of osteoporosis.
Undergoing a Bone Density Test
If a doctor determines that you are at risk for osteoporosis, you may undergo a bone density test. A common example is a dual energy X-ray absorptiometry (DEXA) scan. This painless, rapid test uses X-ray images to measure bone density and fracture risk.
Performing Blood and Urine Testing
Medical conditions can cause bone loss. This includes parathyroid and thyroid malfunctioning. A doctor may perform blood and urine testing to rule this out. Examples include testing calcium levels, thyroid function and testosterone levels in men.
The BMD Test
According to the Radiological Society of North America (RSNA), a DEXA scan is the standard for measuring how the density of a person’s bones and their risk for osteoporosis. This painless test uses X-rays to measure bone density.
A radiation technologist performs a DEXA scan using a central or peripheral device. A central device is more commonly used in a hospital or doctor’s office. The person lies on a table while a scanner is used to measure hip and spine bone density.
A peripheral device is more commonly used at mobile health fairs or pharmacies. Doctors call peripheral tests “screening tests.” The device is smaller and box-like. You can place a foot or arm in the scanner to measure bone mass.
According to the RSNA, the test takes anywhere from 10 to 30 minutes to perform. Doctors may also perform an additional test known as a lateral vertebral assessment (LVA). Since back pain is both a frequent symptom of vertebral fractures from osteoporosis and a common symptom in general, LVA has been assessed to determine whether it can help doctors differentiate osteoporosis from non-specific back pain. This test uses DEXA machinery to help determine if someone already has spinal fractures. The overall clinical utility of this test in the diagnosis and management of osteoporosis remains controversial.
DEXA imaging results include two scores: a T score and a Z score. The T score compares a person’s bone mass with a young adult’s of the same gender. According to the National Osteoporosis Foundation, the scores are the following.
- greater than -1: normal
- -1 to -2.5: low bone mass (called osteopenia, a potential precursor condition to osteoporosis)
- less than -2.5: typically indicates osteoporosis
A Z score compares a person’s bone mineral density to that of people their same age, gender, and overall body type. If your Z score is below -2, something other than normal aging may be responsible for your declining bone mineral density and prompt further testing.
These diagnostic tests don’t mean you will definitely experience osteoporosis or a bone fracture. Instead, they assist your doctor in assessing your risk. They also cue a doctor that further treatment may be needed and should be discussed.
A DEXA is not expected to cause pain. However, it does involve some minor radiation exposure. According to the RSNA, the exposure is one-tenth that of a traditional X-ray.
Women who could potentially be pregnant may be advised against the test. If there is indication of a high osteoporosis risk in a pregnant woman, she may want to consider discussing the pros and cons of DEXA testing with her doctor.
You don’t have to eat a special diet or refrain from eating before a DEXA test. However, a doctor may recommend refraining from taking calcium supplements a day before the test.
A woman should also inform the X-ray technologist if there is any possibility she could be pregnant. A doctor may postpone the test until after the baby is delivered or recommend ways to minimize radiation exposure.
Doctors use testing results to make treatment recommendations for people with osteopenia and osteoporosis. Some people may need to make lifestyle changes. Others may require medications.
According to the American College of Rheumatology, people with a low bone density score may also receive a fracture risk assessment (FRAX) score. This score predicts the likelihood a person will experience a bone break in the next decade. Doctors use FRAX scores and bone mineral density (BMD) test results to recommend treatments.
These scores don’t mean you will progress from osteopenia to osteoporosis or experience a fracture. Instead, they encourage prevention methods. Examples include:
- fall prevention measures
- increasing dietary calcium
- taking medications
- refraining from smoking