A bone density test does not indicate arthritis. Instead, it suggests a person’s bone strength. Doctors use it to diagnose osteoporosis, a condition where the bones weaken and become prone to fractures.

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Since arthritis is a condition that affects the joints, a bone density test is not a tool that doctors use to diagnose the condition. However, they may recommend the test for people with rheumatoid arthritis because they have a higher incidence of osteoporosis than the general population.

This article discusses bone density tests and whether they may be necessary for a person with arthritis. We also examine other arthritis diagnostic tests and other uses for a bone density test.

A bone density test is a painless procedure similar to an X-ray that requires no preparation. The screening takes around 15 minutes and measures the strength, or mineral density, of bone in the hip and lumbar spine.

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Doctors may recommend a peripheral bone density test for screening purposes to determine if a standard bone density test is necessary for some individuals. A peripheral test measures bone density in the:

  • heel
  • lower arm
  • wrist
  • finger

A bone density test determines whether people may have osteoporosis, a condition involving weakened bones and a higher risk of fractures. The Office of Disease Prevention and Health Promotion states that because osteoporosis has no symptoms, a person may not know they have the condition until they break a bone.

The results of a bone density test commonly consist of a T-score, which compares someone’s bone density with that of a healthy person.

Scores in the “+” range mean an individual has a higher than average bone density, while a score in the “-” range means they have a lower than average bone density. Therefore, the lower the score, the lower the bone density. The scoring system is as follows:

  • Normal: A T-score between +1 and -1.
  • Low bone density: A T-score between -1 and -2.5.
  • Osteoporosis: A T-score of -2.5 or lower.

Bone density test scores do not indicate arthritis, which is an inflammatory condition of the joints. However, a doctor may order this screening for rheumatoid arthritis because people with arthritis also tend to have low bone mineral density.

According to the National Institutes of Health (NIH), individuals with rheumatoid arthritis have a higher risk of osteoporosis due to:

  • treatment involving glucocorticoid drugs, which can cause bone loss
  • inactivity from the pain and loss of joint function associated with the condition
  • bone loss due to the physiology that characterizes rheumatoid arthritis, which is more pronounced in areas surrounding the affected joints

A 2020 study states that osteoporosis in people with rheumatoid arthritis occurs at approximately twice the rate than in the general population. Additionally, individuals with rheumatoid arthritis may experience fractures with higher bone mineral densities.

Because of the strong relationship between rheumatoid arthritis and osteoporosis, the study authors proposed using different techniques to measures bone density in early-diagnosed cases. They said this could help indicate the severity of the condition.

Besides a physical exam, doctors use the following tests to diagnose arthritis:

  • Imaging tests: These tests look for joint inflammation and erosion. Common imaging tests include X-rays, but they may also involve ultrasound and MRIs.
  • Electrodiagnostic test: Indicate a disruption in the electrical activity of the nerves.
  • Blood tests: According to older research, some blood tests are necessary to help diagnose certain types of arthritis, such as rheumatoid arthritis. However, doctors may diagnose other forms of the condition just by looking at a person’s physical symptoms and medical history.
  • Fluid and tissue tests: These tests analyze joint fluid or involve a tissue biopsy from the skin or muscle.

Other reasons for a bone density test, other than diagnosing osteoporosis, include assessing the risk of fractures and monitoring the effectiveness of treatments. Doctors recommend the screening for any person with a higher risk of bone loss, such as:

  • postmenopausal females who do not take estrogen
  • postmenopausal females who have a height of 5 foot 7 inches or a weight of 125 pounds
  • males with a condition relating to bone loss, such as kidney disease or rheumatoid arthritis
  • females who are 65 years of age or older

Practitioners also advise it for those who:

  • have a personal or maternal history of smoking or hip fractures
  • take medications that can cause bone loss, including antiseizure drugs, such as phenytoin (Dilantin), or corticosteroids, such as prednisone (Rayos)
  • have high bone turnover
  • have an illness that increases the risk, such as type 1 diabetes, hyperthyroidism, and hyperparathyroidism

The Arthritis Foundation notes that urgent medical attention is unnecessary for mild or infrequent joint pain. However, if a person has a form of arthritis that causes permanent joint damage, prompt treatment can help preserve joint function.

With this in mind, an individual should watch for these symptoms:

  • redness and warmth in joints
  • swelling, pain, or stiffness in one or more joints
  • joint tenderness
  • difficulty in moving a joint

People should also speak with a doctor if they have joint symptoms that last longer than 3 days or experience several symptoms within a month. They can start with a primary care doctor, although some individuals may need to consult with a rheumatologist who specializes in arthritic conditions.

A bone density test does not show arthritis but reveals the health of the bones rather than the joints. Doctors use it to diagnose the presence and severity of osteoporosis.

People with rheumatoid arthritis have a higher likelihood of bone loss due to several factors. These include the physiological effects of their condition and the inactivity it produces. Adverse reactions to a common medication they take can also be a factor. For these reasons, doctors may advise them to undergo a bone density test.

Because some forms of arthritis can lead to permanent joint damage, a person who experiences joint symptoms several times per month should speak with a doctor. Early diagnosis and treatment can help prevent some of the damage due to the condition.