When is a Dual-Energy X-ray Absorptiometry (DEXA) scan recommended?

DEXA Scan Indications: When to Perform Bone Density Testing

DEXA scans should be performed in all women aged 65 years and older and men aged 70 years and older, as well as in younger individuals with specific risk factors for osteoporosis. 1, 2, 3

General Screening Recommendations

• All women aged 65 years and older should undergo routine DEXA screening regardless of risk factors 1, 2, 3
• All men aged 70 years and older should undergo routine DEXA screening 2, 3
• Routine DEXA screening is not recommended for women younger than 65 years and men younger than 70 years who have no risk factors 2, 3

High-Risk Individuals Requiring Earlier Screening

DEXA screening should be performed in the following individuals regardless of age:

• Postmenopausal women younger than 65 years with risk factors for osteoporosis 1, 2
• Individuals with previous fragility fractures 1, 2
• Individuals with significant height loss (>4 cm or >1.5 inches) 1
• Individuals taking medications associated with bone loss:
  • Long-term glucocorticoid therapy (≥5 mg prednisone daily for ≥3 months) 1
  • Androgen deprivation therapy for prostate cancer 1, 2
  • Aromatase inhibitor therapy 1
  • Anticonvulsant drugs 1
  • Chronic heparin 1
• Individuals with medical conditions associated with bone loss:
  • Hyperparathyroidism 1
  • Hypogonadism 1
  • Chronic inflammatory diseases 3
  • Malabsorption disorders 1
  • Spinal cord injuries (as soon as medically stable) 1, 2
  • Type 1 diabetes 4
• Individuals with low body weight (<127 lb/58 kg) 1
• Individuals with parental history of hip fracture 1
• Transgender individuals with risk factors (especially those on gonadotropin-releasing hormone without sex steroid therapy) 1, 2

Vertebral Fracture Assessment (VFA) Indications

VFA or standard radiography should be performed in:

• Individuals with T-score < -1.0 and one or more of the following:
  • Women aged ≥70 years or men aged ≥80 years 1
  • Historical height loss >4 cm 1
  • Self-reported but undocumented prior vertebral fracture 1
  • Oral glucocorticoid therapy equivalent to ≥5 mg prednisone daily for ≥3 months 1
• Women aged 65+ years with T-score ≤-1.0 at femoral neck 1
• Cases of acute onset back pain with risk factors for osteoporosis 1

Follow-up DEXA Scanning

• For individuals with normal bone density or mild osteopenia: repeat DEXA in 2-3 years 2, 3
• For individuals with osteoporosis or on treatment: repeat DEXA in 1-2 years to monitor treatment effectiveness 1, 2
• For individuals with spinal cord injuries: follow-up DEXA at 1-2 year intervals 1, 2
• Repeat BMD testing should be performed if a fracture has occurred or new risk factors have developed 1
• Follow-up BMD testing should be used to monitor individuals prior to a temporary cessation of bisphosphonate therapy and during the period of planned interruption of treatment 1

Special Considerations

• Z-scores (not T-scores) should be reported for premenopausal women and men <50 years of age 1
• Z-scores should be calculated using reference data conforming with the individual's gender identity for transgender individuals 1, 2
• In men with prostate cancer on androgen deprivation therapy, "secondary osteoporosis" can be selected in FRAX when femoral neck BMD is not available 1

Common Pitfalls in DEXA Interpretation

• Vertebral artifacts that may falsely increase BMD values:
  • Osteoarthritis (especially in older adults) 1
  • Vertebral fractures 1
  • Surgical material and hardware 1
  • Aortic calcifications 1
• Hip artifacts:
  • Hip osteoarthritis 1
  • Arthroplasty or osteosynthesis hardware 1
  • Incorrect rotation of the femur 1

DEXA scanning remains the gold standard for diagnosing osteoporosis and assessing fracture risk, with appropriate timing based on age and risk factors being crucial for effective prevention and management of osteoporosis-related fractures 5, 6.