What are the guidelines for Dual-Energy X-ray Absorptiometry (DEXA) scans for different age groups and risk factors?

DEXA Scan Guidelines for Different Population Groups

The US Preventive Services Task Force recommends DEXA screening for all women aged 65 years or older and selective screening for postmenopausal women younger than 65 years who have elevated risk of osteoporosis based on clinical risk assessment. 1

General Screening Recommendations by Age and Sex

• Women aged 65 years and older should undergo routine DEXA screening regardless of risk factors 1
• Men aged 70 years and older should undergo routine DEXA screening 1
• Postmenopausal women under age 65 with risk factors should be selectively screened based on clinical risk assessment 1, 2
• The American Academy of Family Physicians recommends against routine DEXA screening in women younger than 65 years and men younger than 70 years with no risk factors 1

High-Risk Groups Requiring Earlier Screening

DEXA screening is recommended for the following individuals regardless of age:

• Adults with a previous fragility fracture 1, 3
• Individuals on long-term glucocorticoid therapy (≥5 mg prednisone or equivalent daily for ≥3 months) 1, 4
• Individuals with medical conditions associated with bone loss such as:
  • Hyperparathyroidism 1
  • Chronic inflammatory diseases 4
  • Malabsorption syndromes 4
  • Hypogonadism 1
• Individuals with untreated premature menopause 4, 2
• Individuals taking medications associated with bone loss 1, 2
• Individuals with spinal cord injuries (as soon as medically stable) 1
• Individuals undergoing androgen deprivation therapy for prostate cancer 1

Vertebral Fracture Assessment (VFA) Indications

VFA or standard radiography is recommended for:

• T-score < -1.0 with one or more of the following:

  • Women aged ≥70 years or men aged ≥80 years 1
  • Historical height loss >4 cm (>1.5 inches) 1
  • Self-reported but undocumented prior vertebral fracture 1
  • Oral glucocorticoid therapy equivalent to ≥5 mg prednisone daily for ≥3 months 1

• Additional indications from the Bone Health & Osteoporosis Foundation:

  • Women aged 65+ years with T-score ≤-1.0 at femoral neck 1
  • Women aged 70+ years or men aged 80+ years with T-score ≤-1.0 at lumbar spine, total hip, or femoral neck 1
  • Men aged 70-79 years with T-score ≤-1.5 at lumbar spine, total hip, or femoral neck 1

Screening Intervals

• For individuals with normal bone density or mild osteopenia: repeat DEXA in 2-3 years 1
• For individuals with osteoporosis or on treatment: repeat DEXA in 1-2 years to monitor treatment effectiveness 1
• For individuals with spinal cord injuries: follow-up DEXA at 1-2 year intervals 1

Special Considerations

Transgender Individuals

• Z-scores should be calculated using reference data conforming with the individual's gender identity 1
• For gender non-conforming individuals, reference data for sex recorded at birth should be used 1
• Post-pubertal transgender youth on gonadotropin-releasing hormone without sex steroid therapy may be at risk for decreasing bone density 1

Common Pitfalls in DEXA Interpretation

• Proper positioning is essential for accurate results - use the PARED approach:

  • P - Positioning (correct patient positioning)
  • A - Artifacts (identify any artifacts within region of interest)
  • R - Regions of Interest (verify correct placement)
  • E - Edge Detection (ensure proper edge detection)
  • D - Demographics and Database (verify correct reference database) 1

• Artifacts in the lumbar spine can cause spurious increases in BMD values (most common with osteoarthritis) 1

• Two-dimensional projection images may underestimate true volumetric bone density in short individuals or overestimate in tall individuals 1

Fracture Risk Assessment

• FRAX or other validated tools should be used to calculate 10-year fracture risk 2
• DEXA should be considered if the 10-year risk of major osteoporotic fracture is >10% 4
• In men with prostate cancer on androgen deprivation therapy, "secondary osteoporosis" can be selected in FRAX when femoral neck BMD is not available 1

By following these guidelines, clinicians can appropriately identify individuals who would benefit from DEXA screening and subsequent intervention to reduce fracture risk and improve outcomes.