At what age is a Dual-Energy X-ray Absorptiometry (Dexa) scan recommended for men and women with varying risk factors and medical histories?

DEXA Scan Age Recommendations

All women should begin routine DEXA screening at age 65 years and all men at age 70 years, regardless of risk factors. 1, 2

Standard Screening Ages by Sex

Women

• Routine screening begins at age 65 years for all women, with no additional risk factors required 1, 2
• Screening is NOT recommended for women younger than 65 years without documented risk factors 1, 2

Men

• Routine screening begins at age 70 years for all men, regardless of risk factors 1, 2
• Screening is NOT recommended for men younger than 70 years without documented risk factors 1, 2

Earlier Screening for High-Risk Individuals (Any Age)

The following conditions justify DEXA screening before the standard age cutoffs:

Previous Fracture History

• Any adult with a previous fragility fracture should undergo immediate DEXA screening, regardless of age 1, 3
• The presence of any prevalent fracture increases future fracture risk by approximately 2-fold or more 4

Medication-Related Risk Factors

• Individuals receiving or expected to receive glucocorticoid therapy for >3 months require DEXA screening 5, 1
• Glucocorticoid-induced osteoporosis causes fractures at higher BMD levels than postmenopausal osteoporosis (treatment threshold T-score of -1.5 rather than -2.5) 6
• Individuals on androgen deprivation therapy for prostate cancer 5, 1
• Individuals on aromatase inhibitor therapy 5
• Individuals on chronic anticonvulsant drugs or chronic heparin therapy 5

Endocrine and Metabolic Conditions

• Hypogonadal men >18 years of age and men with surgically or chemotherapeutically induced castration 5
• Individuals with hyperparathyroidism, hyperthyroidism, or Cushing syndrome 5
• Postmenopausal women under 65 with early menopause 2

Other Medical Conditions

• Chronic alcoholism or established cirrhosis 5, 3
• Rheumatoid arthritis or other chronic inflammatory arthritides 5
• Eating disorders including anorexia nervosa and bulimia 5
• Organ transplantation 5
• Spinal cord injury (screen as soon as medically stable) 1, 3
• Gastrointestinal malabsorption, malnutrition, sprue, or vitamin D deficiency 5
• Prolonged immobilization 5

Clinical Risk Assessment for Postmenopausal Women Under 65

• Postmenopausal women under 65 with 10-year major osteoporotic fracture risk ≥9.3% as calculated by FRAX should undergo DEXA screening 1, 2
• Body weight less than 127 pounds (approximately 58 kg) 2
• Parental history of hip fracture 2

Screening Intervals After Initial DEXA

Normal or Mild Osteopenia

• Repeat DEXA in 2-3 years for individuals with normal bone density or mild osteopenia 1, 2
• For individuals with normal baseline BMD (T-score ≥-1) and no major risk factors, serial BMD measurements every 24 months are not necessary, as progression to treatment threshold takes approximately 16 years 4

Osteoporosis or On Treatment

• Repeat DEXA in 1-2 years for individuals with osteoporosis or on treatment to monitor treatment effectiveness 1, 2

High-Risk for Accelerated Bone Loss

• Repeat DEXA in 1-2 years for individuals at high risk for accelerated bone loss (glucocorticoid therapy, spinal cord injury) 5, 1

Critical Pitfalls to Avoid

Age-Related Errors

• Do not screen women under 65 or men under 70 without documented risk factors - this exposes patients to unnecessary radiation and costs without clinical benefit 2
• Do not delay screening in patients with chronic alcoholism, early menopause, or glucocorticoid use - these conditions justify earlier screening regardless of age 2, 3

Interval-Related Errors

• Never repeat DEXA at intervals less than 1 year under any circumstances 1
• Do not repeat DEXA scans more frequently than every 2 years in patients with normal BMD - testing precision limitations make shorter intervals unreliable and clinically meaningless 1, 2
• A minimum of 2 years is needed to reliably measure a change in BMD due to limitations in testing precision 1

Risk Assessment Errors

• Do not assume obesity provides adequate protection against osteoporosis when other major risk factors are present 3
• Higher body weight is actually protective against osteoporosis, not an indication for screening 3
• Do not overlook men after fractures - men account for 24% of hip fractures and 21% of wrist fractures but only receive 10% of BMD tests 4

Scan Technique

• Scan both lumbar spine and bilateral hips in all patients 5, 2
• Use T-scores for all postmenopausal women regardless of age 2
• Use Z-scores for premenopausal women and men under 50 2
• **Consider Vertebral Fracture Assessment (VFA) during the same session for patients with T-score <-1.0 and one or more of the following:** women ≥70 years or men ≥80 years, historical height loss >4 cm, self-reported prior vertebral fracture, or glucocorticoid therapy ≥5 mg prednisone daily for ≥3 months 5, 1