What are the recommendations for DEXA (Dual-Energy X-ray Absorptiometry) scan screening?

DEXA Screening Recommendations

All women aged 65 years and older should undergo routine DEXA screening regardless of risk factors, and all men aged 70 years and older should undergo routine DEXA screening. 1, 2, 3

Standard Age-Based Screening

Women

• Screen all women at age 65 or older with DEXA of the lumbar spine, total hip, femoral neck, and if indicated, one-third radius 1, 2
• Do not routinely screen women younger than 65 years unless they have specific risk factors 2, 3

Men

• Screen all men at age 70 or older with DEXA 1, 2, 3
• Do not routinely screen men younger than 70 years unless they have specific risk factors 2, 3
• Evidence for screening men remains limited, with inadequate data on fracture reduction from treatment in men without prior fractures 1

Early Screening for High-Risk Individuals (Before Standard Age Thresholds)

Screen postmenopausal women under 65 years and men under 70 years if they have any of the following risk factors:

Fracture History

• Previous fragility fracture (low-trauma fracture of hip, spine, forearm, humerus, or pelvis) 1, 2, 3

Medication-Related Risk

• Long-term glucocorticoid therapy (≥5 mg prednisone daily for ≥3 months) 1, 2, 3
• Androgen deprivation therapy for prostate cancer 2, 3
• Other medications associated with bone loss 2, 3

Medical Conditions

• Hyperparathyroidism or hypogonadism 2, 3
• Chronic inflammatory diseases 3
• Spinal cord injuries (screen as soon as medically stable) 2, 3
• Klinefelter syndrome (screen starting at age 20-50 years) 4
• HIV infection (postmenopausal women and men ≥50 years) 3

Clinical Risk Factors

• Body weight less than 127 pounds (58 kg) 1
• Parental history of hip fracture 1
• 10-year major osteoporotic fracture risk ≥9.3% as calculated by FRAX 2, 3

Vertebral Fracture Assessment (VFA) Indications

Perform VFA or standard radiography in patients ≥50 years with:

• T-score < -1.0 AND any of the following: 1, 2
  • Women aged ≥70 years or men aged ≥80 years
  • Historical height loss >4 cm
  • Self-reported but undocumented vertebral fracture
  • Long-term glucocorticoid therapy

Follow-Up Screening Intervals

Normal Bone Density or Mild Osteopenia

• Repeat DEXA in 2-3 years 2, 3
• For women with completely normal BMD at age 65, intervals can extend to 4-8 years, as the transition to osteoporosis takes approximately 17 years 2
• Never repeat scans more frequently than every 2 years unless on high-risk medications, as testing precision limitations prevent reliable measurement of change 2

Osteoporosis or On Treatment

• Repeat DEXA in 1-2 years to monitor treatment effectiveness 1, 2, 3

High-Risk Conditions

• Glucocorticoid therapy: 1-2 year intervals 2
• Spinal cord injuries: 1-2 year intervals 2, 3
• HIV patients not requiring treatment: 2-5 years depending on proximity to treatment thresholds 3

Moderate Osteopenia

• For baseline T-score in the -1.50 to -1.99 range, transition to osteoporosis occurs over approximately 5 years, so repeat in 2-3 years 2
• Do not repeat routinely if T-score ≥-2.0 unless new risk factors develop 2

Diagnostic Criteria

Diagnose osteoporosis when T-score is ≤-2.5 at any measured site (lumbar spine, femoral neck, total hip, or one-third radius), using the lowest T-score for diagnosis 1

• Use NHANES III reference database for T-score calculation based on 20-29 year old White women 1
• Some societies presume osteoporosis diagnosis with low-trauma major fracture even without DEXA confirmation 1

Critical Pitfalls to Avoid

• Do not screen too frequently: Intervals <2 years expose patients to unnecessary radiation and costs without clinical benefit in stable patients 2
• Do not wait until standard age thresholds for high-risk conditions: Patients with Klinefelter syndrome, spinal cord injuries, or on androgen deprivation therapy require earlier screening 2, 3, 4
• Do not forget to assess for new risk factors at each clinical encounter, including height loss >4 cm, new medications affecting bone metabolism, or development of conditions associated with bone loss 2
• Ensure same facility and machine for follow-up when possible, as different DXA machines may show measurement variation unless cross-calibrated 2
• Do not rely solely on FRAX: While recommended for risk assessment, FRAX has limitations and should be used in conjunction with clinical judgment 3