T-Score Range for Osteopenia
According to the World Health Organization (WHO) diagnostic criteria, osteopenia is defined as a T-score between -1.0 and -2.5 as measured by dual-energy X-ray absorptiometry (DEXA). 1
Diagnostic Classification of Bone Mineral Density
The WHO and National Osteoporosis Foundation have established the following classification system:
| Category | T-score |
|---|---|
| Normal BMD | ≥ -1.0 |
| Osteopenia/low bone mass | -1.0 to -2.5 |
| Osteoporosis | ≤ -2.5 |
This classification system is widely accepted and used as the standard for diagnosing bone density disorders 1, 2.
Important Considerations for T-Score Interpretation
- T-scores are the primary diagnostic parameter for osteoporosis in adults ≥40 years, while Z-scores are more important for younger individuals 1
- The diagnosis of osteopenia alone is not an indication for treatment 3, 4
- Fracture risk varies widely within the osteopenic range, depending on multiple factors 5
Risk Assessment for Patients with Osteopenia
For patients with T-scores in the osteopenic range, additional risk assessment is crucial:
- Use the FRAX tool to calculate 10-year fracture probability 1
- Consider treatment if 10-year probability of hip fracture is ≥3% or major osteoporotic fracture is ≥20% 1
- Evaluate for vertebral fractures using Vertebral Fracture Assessment (VFA), especially in:
- Women ≥70 years or men ≥80 years
- Historical height loss >4 cm
- Self-reported prior vertebral fracture
- Glucocorticoid therapy 6
Clinical Significance of Osteopenia
- More than 60% of white women older than 64 years have osteopenia 5
- The majority of osteoporotic fractures occur in individuals with BMD T-scores in the osteopenic range 4, 5
- Despite this, widespread medication use based solely on T-score in the osteopenic range is not advisable due to high number needed to treat (NNT>100) 4
Management Recommendations
For patients with osteopenia:
- Ensure adequate calcium (1,000-1,200 mg daily) and vitamin D (600-800 IU daily) intake 1
- Recommend weight-bearing exercise and resistance training 1, 6
- Smoking cessation and limiting alcohol consumption 1
- Consider pharmacologic therapy only if additional risk factors are present or FRAX scores indicate high fracture risk 1, 4
Common Pitfalls to Avoid
- Misinterpreting osteopenia as a disease rather than a risk factor 3
- Overlooking age context when interpreting T-scores 1
- Relying solely on BMD without considering other clinical risk factors 1
- Initiating pharmacologic treatment based on T-score alone without considering overall fracture risk 1, 4
Remember that osteopenia is not a disease but rather a description of bone density that falls below normal but is not as low as osteoporosis 2, 3. Management decisions should be based on comprehensive fracture risk assessment rather than T-score alone.