While bone health is often associated with women, men also face risks related to bone weakening and fractures. A standard bone density test is a common assessment method, but the Trabecular Bone Score (TBS) offers a different perspective on bone strength. Understanding the TBS, its normal range for men, and its use can provide a more complete picture of skeletal health.
Understanding the Trabecular Bone Score
Trabecular bone, also known as spongy bone, is the internal, honeycomb-like tissue found inside larger bones, particularly in the spine, hip, and wrist. Its structure provides strength and flexibility, acting as a shock absorber. The Trabecular Bone Score is an index that evaluates this tissue’s microarchitecture by analyzing the texture from a standard spinal bone scan image.
A TBS differs from a Bone Mineral Density (BMD) test. A BMD test measures the quantity of minerals, like calcium, within a bone to determine its mass. In contrast, TBS assesses the quality of the bone’s structure. A helpful analogy is to think of BMD as the total material available to build a bridge, while TBS represents the quality of the engineering and how well those materials are assembled to create a strong, stable structure.
This evaluation of bone quality provides fracture risk information independent of bone density. A person might have a normal BMD measurement but poor trabecular structure, making them more susceptible to fractures. The TBS is not a separate scan; it is calculated using software applied to images from a standard dual-energy X-ray absorptiometry (DXA) scan of the lumbar spine. This provides more comprehensive information without additional scan time or radiation exposure.
Normal TBS Score Ranges for Men
Clinicians interpret a man’s Trabecular Bone Score using standardized ranges that correlate with fracture risk. A higher score indicates a healthier, more robust bone structure, while a lower score suggests a weaker structure that is more susceptible to fracture.
A score of 1.310 or higher is considered normal, indicating healthy bone microarchitecture and a low risk of fracture. Scores falling between 1.230 and 1.310 are classified as indicating partially degraded microarchitecture. This intermediate range suggests some loss of bone quality and a moderate risk of fracture.
A score at or below 1.230 signifies degraded microarchitecture and a high risk for fracture. Men with scores in this range have a fragile trabecular network that can compromise bone strength, even if their bone density measurements are not in the osteoporotic range.
TBS values naturally decline with age, but these benchmarks are the most common for assessing risk in clinical practice.
Factors Influencing a Man’s TBS Score
A man’s Trabecular Bone Score can be influenced by lifestyle choices, medical issues, and certain medications. Smoking and excessive alcohol consumption have a detrimental effect on bone microarchitecture. A sedentary lifestyle without regular weight-bearing exercise also fails to provide the stress needed to stimulate bone maintenance.
Certain medical conditions can cause poor bone quality and a lower TBS score. Type 2 diabetes can negatively affect bone structure even when bone density appears normal. Other conditions, such as hyperparathyroidism and inflammatory diseases like rheumatoid arthritis, can also degrade the trabecular network.
Specific medications can also impact bone quality. Long-term use of glucocorticoids, a class of steroids like prednisone, is known to degrade bone microarchitecture. These drugs interfere with the body’s bone remodeling process, leading to a weaker internal structure over time.
How TBS Is Used in Clinical Practice
In a clinical setting, the Trabecular Bone Score is not typically used as a standalone diagnostic tool. Instead, it serves as a valuable supplement to the standard Bone Mineral Density (BMD) test. Its primary application is to refine a patient’s overall fracture risk assessment, providing a more nuanced and accurate picture of their bone health.
The score is most often used to adjust results from the Fracture Risk Assessment Tool (FRAX). FRAX is an algorithm that calculates a person’s 10-year probability of a major osteoporotic fracture. The calculation incorporates femoral neck BMD along with clinical risk factors like age, sex, body mass index, and a history of previous fractures.
By incorporating the TBS, a clinician can modify the FRAX score to better reflect bone quality. For instance, if a man has a borderline FRAX score but a low TBS, the doctor may adjust the fracture probability upward. This integrated approach creates a more personalized risk profile, guiding decisions on preventative measures, lifestyle changes, or medical treatment.