What are the recommendations for bone density tests in females, particularly those over 65 or postmenopausal, to assess the risk of osteoporosis?

Bone Density Testing Recommendations for Females

All women aged 65 years and older should undergo routine bone density screening for osteoporosis using dual-energy X-ray absorptiometry (DXA), while women aged 60-64 with risk factors should begin screening earlier. 1, 2

Screening Recommendations by Age Group

Women 65 years and older

• Universal screening with DXA regardless of risk factors 2, 1
• Femoral neck measurement by DXA is the best predictor of hip fracture 2
• No established upper age limit for screening, though data on treatment benefits for women >85 years is limited 2

Women 60-64 years

• Selective screening recommended for those with increased risk factors 2, 1
• Risk factors that warrant earlier screening:
  • Low body weight (<70 kg/154 lbs) - strongest single predictor 2
  • No current use of estrogen therapy 2
  • Prior fracture history 3
  • Family history of osteoporotic fractures 1
  • Smoking 1
  • Excessive alcohol intake 1
  • Physical inactivity 1
  • Early menopause or premature ovarian failure 1

Women under 60 years

• Routine screening not recommended unless significant risk factors present 2
• Consider screening in postmenopausal women with fracture history 1

Risk Assessment Tools

For women aged 50-64, risk assessment tools can help identify candidates for early screening:

• FRAX (Fracture Risk Assessment Tool): Calculates 10-year probability of major osteoporotic fracture and hip fracture 1, 4
• OST (Osteoporosis Self-Assessment Tool): Simple tool using age and weight 1
• ORAI (Osteoporosis Risk Assessment Instrument): Evaluates key risk factors including weight, age, and estrogen use 2, 1

Diagnostic Criteria

DXA results are interpreted using T-scores according to WHO classification 1:

• Normal: T-score > -1.0
• Osteopenia: T-score between -1.0 and -2.4
• Osteoporosis: T-score ≤ -2.5

Follow-up Testing

• Minimum interval of 2 years between DXA scans due to limitations in testing precision 2, 1
• Use the same DXA machine for follow-up scans 1
• Compare absolute BMD values (g/cm²), not T-scores, when monitoring changes 1
• More frequent testing (annually) may be appropriate for patients:
  • On glucocorticoid therapy 1
  • At risk for rapid bone loss 1
  • Initiating osteoporosis treatment 1

Important Clinical Considerations

• African-American women generally have higher bone mineral density than white women at the same age and may benefit less from routine screening 2
• Diagnosis of osteoporosis persists even if subsequent DXA T-scores improve to above -2.5 with treatment 5
• A prior low-trauma fracture may warrant presumptive diagnosis of osteoporosis even with normal BMD 1
• Treatment decisions should be based on absolute fracture risk rather than T-scores alone 3, 5

Common Pitfalls to Avoid

1. Incorrect site measurement: Ensure proper measurement at femoral neck, total hip, lumbar spine, or one-third radius 1
2. Comparing T-scores instead of absolute BMD values when monitoring treatment response 1
3. Using different DXA machines for baseline and follow-up measurements 1
4. Failing to account for artifacts or degenerative changes that may falsely elevate BMD readings 1
5. Not recognizing that fracture risk depends on multiple factors, not just BMD 3, 4

By following these evidence-based recommendations for bone density testing, clinicians can identify women at risk for osteoporotic fractures and initiate appropriate interventions to reduce morbidity and mortality associated with fragility fractures.