A bone densitometry (density test) helps determine your overall bone mass, along with your risk for fractures.
While a bone density test alone can’t determine whether you have arthritis, your doctor may order one if you have inflammatory types of joint disease, as these can be risk factors for bone loss.
Curious about whether you’re a candidate for a bone density test? Learn more about what this type of measurement test reveals, and why your doctor may order one if you have arthritis.
As the name suggests, a bone mineral density test measures the density, or mass, of your bones. This helps to determine overall bone strength while also detecting weaknesses that could potentially lead to fractures.
This type of test is primarily used to diagnose either osteopenia or osteoporosis. Osteopenia is an early loss of bone mass, and is considered a precursor to osteoporosis. Unlike osteoporosis, there aren’t any symptoms of osteopenia, and it’s usually found via bone density tests.
Inflammatory arthritis may also increase your risk of developing osteoporosis for the following reasons:
- joint inflammation may trigger bone loss in surrounding areas
- common medications, like glucocorticoids, may speed up bone loss and also decrease calcium and vitamin D metabolism
- reduced activity levels due to pain and overall loss of joint function
But this type of test is not a first-line diagnostic tool for arthritis alone because it focuses on bone mass rather than joint damage.
A bone density test is usually performed via a dual-energy X-ray absorptiometry (DXA). In some cases, traditional X-rays or CT scans might be used to measure bone density. These imaging tests provide clear pictures to help your doctor make a more accurate diagnosis.
Once the test is complete, you’re given a “T-score” based on the following scale:
- above -1 to +1: normal bone density
- -1 to -2.5: osteopenia
- -2.5 or lower: osteoporosis
Most bone density tests are used on parts where bone loss may be evident, or where you may be more likely to experience fractures. These include the:
- lower arms
A bone density test may be ordered if your doctor suspects either osteopenia or osteoporosis. Some rheumatologists may also request this test be done if you have RA or PsA. The purpose is to help determine whether you need to be treated for bone loss before it leads to fractures.
Your doctor may also recommend bone density tests if you have any of the following chronic illnesses:
Other candidates for bone density tests include those who:
- are men over the age of 70 or women over the age of 65, according to Johns Hopkins Medicine
- have a history or osteopenia
- had early menopause (in women)
- have family history or osteopenia or osteoporosis
- are smokers or consume alcohol excessively
- have a low body mass index (BMI)
- chronically use proton pump inhibitors for heartburn
- take other steroids or anticonvulsants on a long-term basis
There are more than 100 types of arthritis, so your doctor will run necessary tests and exams to help confirm the correct form.
Arthritis is diagnosed with a combination of:
- health questionnaires, which include information about any family history of arthritis and rheumatic conditions
- physical exams
- imaging tests
- blood tests
While occasional joint pain doesn’t automatically mean arthritis, early signs of joint damage may include pain that increasingly worsens overtime. You may feel joint pain every day, and it can be significant enough to interfere with your daily activities.
In cases of RA, you may also notice redness and warmth around the affected joints. This is caused by inflammation in the joints. PsA can also cause these symptoms, along with skin patches (psoriasis).
To confirm arthritis, your doctor may also use imaging tests like X-rays. Ultrasounds may also be used. These pictures will detail joint damage along with inflammation.
Traditional X-rays used to diagnose arthritis differ from specialized DXA versions because they lack the technology used to measure bone mineral density. Depending on your circumstances, multiple types of imaging tests may be used.
Depending on your doctor’s findings, a blood test may be ordered to confirm inflammatory types of arthritis only.
A bone density test isn’t typically used to diagnose arthritis. Instead, it’s most often used to diagnose early signs of bone loss or osteoporosis.
But if you have inflammatory types of arthritis, like RA or PsA, you may be at risk for developing osteoporosis. Thus, your rheumatologist may order a bone density test to assess your overall bone mass if you’re considered at risk.
Medications for inflammatory arthritis could accelerate bone loss, particularly if you’re postmenopausal. Other risk factors include lack of exercise due to joint pain and discomfort.
If you have risk factors for osteoporosis, or currently have arthritis and are concerned about bone loss, talk with a doctor about the possibility of receiving a bone density test. Due to exposure to radiation with this test, your doctor will consider your risk factors carefully.