Understanding Bone Density Tests
A bone density test, most commonly a DEXA (dual-energy X-ray absorptiometry) scan, is a quick, painless, and non-invasive procedure that measures bone mineral density (BMD). By quantifying the mineral content in your bones, typically at the hip and spine, the test helps determine your bone strength and assess your risk of developing osteoporosis. Osteoporosis, often called a 'silent disease,' causes bones to become porous and brittle, leading to an increased risk of fractures. Early detection through a bone density test is the most effective way to prevent or manage this condition.
Screening Recommendations by Gender and Age
Official guidelines for when to get a bone density test differ for men and women. These recommendations are based on research into the typical progression of bone loss in different populations and the effectiveness of screening at certain ages. It's important to discuss these guidelines with your healthcare provider to create a personalized screening plan.
Guidelines for Women
- Age 65 and older: The U.S. Preventive Services Task Force (USPSTF) recommends routine osteoporosis screening for all women 65 years and older.
- Postmenopausal women under 65: Screening is recommended for postmenopausal women under 65 who are at an increased risk of osteoporotic fracture. This risk is typically determined by using a clinical risk assessment tool and considering specific risk factors.
- Menopausal transition and high-risk women: Some organizations suggest earlier screening for women in the menopausal transition, especially if they have risk factors like low body weight, prior fractures, or a history of heavy smoking.
Guidelines for Men
- Age 70 and older: Many organizations, including the Bone Health & Osteoporosis Foundation, recommend that all men aged 70 and older undergo bone density screening.
- Men aged 50-69 with risk factors: Screening is also recommended for men aged 50 to 69 who have significant risk factors for osteoporosis.
- Risk assessment: While evidence is still considered insufficient for universal screening in men, healthcare providers should use their clinical judgment to evaluate individual risk and determine the need for a DEXA scan.
Key Risk Factors that Indicate Earlier Testing
Age is a major factor, but not the only one. For both men and women, several other risk factors can necessitate a bone density test at an earlier age. Identifying these factors is key to proactive bone health management.
Health and Lifestyle Factors
- History of fractures: A previous fragility fracture (a break from a fall from standing height or less) as an adult is one of the strongest indicators of bone disease and warrants further assessment, regardless of age.
- Family history: A family history of osteoporosis, particularly a parental history of hip fracture, increases your risk.
- Low body weight: A low body mass index (BMI), often defined as below 21 kg/m², is linked to lower bone density.
- Substance use: Long-term tobacco use and excessive alcohol consumption are known to negatively impact bone health.
- Certain medications: Chronic use of medications such as oral corticosteroids, blood thinners, and certain cancer treatments can accelerate bone loss.
- Underlying medical conditions: Diseases like rheumatoid arthritis, type 1 diabetes, hyperthyroidism, and hyperparathyroidism can increase osteoporosis risk.
- Significant height loss: Progressive height loss of more than 1.5 inches for women or 2 inches for men may suggest undiagnosed vertebral fractures and should prompt a test.
Comparing Bone Density Screening Guidelines
While there is general consensus, different medical organizations may have slightly varying specific recommendations. This table outlines some of the key differences to provide a clearer picture.
| Organization | Women ≥ 65 Years | Men ≥ 70 Years | Younger Adults with Risk Factors |
|---|---|---|---|
| U.S. Preventive Services Task Force (USPSTF) | Recommends screening. | Evidence is insufficient to assess benefits/harms. | Recommends screening for postmenopausal women under 65 at increased risk. |
| Bone Health & Osteoporosis Foundation (BHOF) | Recommends screening. | Recommends screening. | Recommends screening for postmenopausal women and men aged 50-69 with risk factors. |
| American College of Physicians (ACP) | Recommends screening. | Recommends individualized risk assessment, DEXA only for high-risk candidates. | Does not provide specific recommendations for younger women. |
What to Expect from a DEXA Scan
A DEXA scan is a simple and quick procedure, often taking only 15–20 minutes. During the test, you will lie on a padded table while a scanner passes over your hip and spine. The machine uses a very low dose of radiation to measure the bone's mineral content. The results, typically available within a few days, are presented as T-scores and Z-scores.
- T-score: Compares your BMD to that of a healthy young adult. This score is used to diagnose osteoporosis in postmenopausal women and men over 50. A T-score of -1.0 or higher is normal, between -1.0 and -2.5 indicates osteopenia (low bone mass), and -2.5 or lower indicates osteoporosis.
- Z-score: Compares your BMD to that of others in your same age, sex, and ethnic group. A low Z-score may suggest an underlying medical condition is causing bone loss and is typically used for diagnosing younger adults.
Conclusion
Understanding at what age they do a bone density test is a vital step in prioritizing your bone health. For women, screening is recommended for all over 65 and for postmenopausal women under 65 with risk factors. For men, screening is typically advised for those over 70 or for men aged 50-69 with risk factors. If you have any significant risk factors, such as a prior fracture or certain medical conditions, it is important to speak with your doctor about starting screening earlier. Early detection through a DEXA scan and subsequent treatment can dramatically reduce the risk of fractures and improve your quality of life as you age. For more information on bone health, you can visit the Bone Health and Osteoporosis Foundation website.
