At what age or under what conditions should a Dual-Energy X-ray Absorptiometry (DEXA) scan be initiated?

When to Start DEXA Scanning

DEXA scanning should begin at age 65 for all women and age 70 for all men, with earlier screening for individuals with specific risk factors. 1

Age-Based Recommendations

• Women aged 65 years and older should undergo routine DEXA scanning regardless of other risk factors 1
• Men aged 70 years and older should undergo routine DEXA scanning regardless of other risk factors 2
• For younger adults, DEXA testing is recommended only for those with specific risk factors 1

Risk Factor-Based Recommendations for Earlier Screening

For Women Under 65:

• Previous fragility fracture 1
• Estrogen deficiency 1
• Maternal hip fracture history (after age 50) 1
• Low body mass (<127 lb or 57.6 kg) 1
• History of amenorrhea (>1 year before age 42) 1
• Current cigarette use 1
• Height loss or thoracic kyphosis 1

For Men Under 70:

• Previous fragility fracture 2
• Long-term glucocorticoid therapy 2
• Hypogonadism or androgen deprivation therapy 2
• Height loss >4 cm 2
• Low body weight (BMI <20-25 kg/m²) 2

For Both Men and Women (Any Age):

• Medical conditions that affect bone health: 1, 2

  • Chronic renal failure
  • Rheumatoid arthritis and inflammatory arthritides
  • Eating disorders
  • Organ transplantation
  • Prolonged immobilization
  • Gastrointestinal malabsorption or malnutrition
  • Chronic alcoholism or established cirrhosis
  • Multiple myeloma
  • Endocrine disorders (hyperparathyroidism, hyperthyroidism, Cushing syndrome)

• Medication use: 1, 2

  • Glucocorticoid therapy for >3 months
  • Anticonvulsant drugs
  • Androgen deprivation therapy
  • Aromatase inhibitor therapy
  • Chronic heparin

Special Populations

• Individuals with prostate cancer on androgen deprivation therapy should have baseline DEXA scanning before or within 6 months of starting therapy 2
• Individuals with spinal cord injuries should have DEXA scanning as soon as medically stable 2
• Individuals with bone mass osteopenia or fragility fractures identified on other imaging studies 1

Follow-Up Recommendations

• High risk for accelerated bone loss: Follow-up every 1-2 years 1, 2
• Stable risk factors: Follow-up every 2 years 1, 2
• Normal BMD without risk factors: No immediate repeat testing needed 3

Common Pitfalls and Caveats

• Degenerative changes in the spine can falsely elevate BMD values, requiring careful inspection of images 1, 3
• Men are significantly undertested, accounting for 24% of hip fractures but only 10% of BMD tests 2
• Only 19% of people over 65 undergo BMD testing after a fracture, with rates in men only half those in women 2
• Screening before age 65 in women without risk factors may not be cost-effective, as osteoporosis is infrequent until this age 4
• DXA may underestimate fracture risk in certain conditions such as glucocorticoid-induced osteoporosis and type 2 diabetes 2
• Weight alone is an ineffective predictor of low BMD (area under ROC = 70%) 4

Interpretation of Results

• In individuals ≥50 years: T-scores are used (osteoporosis: T-score ≤-2.5; osteopenia: T-score between -1 and -2.5) 2
• In individuals <50 years: Z-scores should be used instead of T-scores, with Z-scores ≤-2.0 defined as "below the expected range for age" 2
• A diagnosis of osteoporosis cannot be made in individuals <50 years based on BMD alone 2