When should a dual‑energy X‑ray absorptiometry (DXA) scan be ordered for women age ≥ 65 years, men age ≥ 70 years, and younger patients with clinical risk factors for osteoporotic fracture?

When to Order DXA Scan

All women aged ≥65 years and all men aged ≥70 years should undergo routine DXA screening regardless of risk factors, while younger postmenopausal women and men aged 50-69 years require DXA only when specific clinical risk factors are present. 1, 2, 3

Standard Age-Based Screening

Universal Screening Thresholds

• Women ≥65 years: Order DXA for all women at this age without requiring additional risk factors—this carries a USPSTF Grade B recommendation (moderate certainty of at least moderate net benefit). 4, 1, 2
• Men ≥70 years: Order DXA for all men at this age regardless of risk profile. 1, 2, 3
• Do NOT screen women <65 years or men <70 years who lack documented risk factors, as this exposes patients to unnecessary radiation and cost without clinical benefit. 3

Rationale for Age Thresholds

• A 65-year-old white woman with no additional risk factors has a baseline 10-year fracture risk of 9.3% using the FRAX tool, which represents the intervention threshold. 4
• By age 65, at least 6% of men have DXA-determined osteoporosis, making systematic screening reasonable at age 70. 3

Earlier Screening for High-Risk Individuals

Postmenopausal Women <65 Years

Order DXA when any of the following risk factors are present: 1, 2, 3

• Previous fragility fracture (fracture from standing height or less)
• Body weight <127 pounds or low BMI
• Parental history of hip fracture
• Early menopause (before age 45)
• 10-year FRAX major osteoporotic fracture risk ≥9.3% (calculated without BMD)
• Chronic glucocorticoid therapy (≥3 months at ≥5 mg prednisone-equivalent daily) 1, 2

Men Aged 50-69 Years

Order DXA when any of the following conditions exist: 1, 3, 5

• Hypogonadism or surgically/chemotherapeutically induced castration
• Androgen deprivation therapy for prostate cancer
• Previous fragility fracture
• Chronic glucocorticoid use (≥3 months)
• Spinal cord injury
• Chronic alcoholism

Medical Conditions Warranting DXA at Any Age

Order DXA regardless of age or sex when these secondary causes of osteoporosis are present: 1, 2, 3

Endocrine disorders:

• Hyperparathyroidism, hyperthyroidism, Cushing syndrome 1, 2

Chronic diseases:

• Chronic renal failure 2
• Rheumatoid arthritis or chronic inflammatory arthritides 1, 2
• Chronic alcoholism or established cirrhosis 1, 2
• Eating disorders (anorexia nervosa, bulimia) 1, 2

Gastrointestinal conditions:

• Malabsorption syndromes, sprue, vitamin D deficiency 1

Other high-risk situations:

• Organ transplantation 1, 2
• Prolonged immobilization 1, 2
• Spinal cord injury (scan as soon as medically stable) 1, 2

High-Risk Medications

Order DXA for patients on: 1, 2, 3

• Aromatase inhibitor therapy (breast cancer treatment)
• Chronic anticonvulsant drugs
• Chronic heparin therapy
• Depot medroxyprogesterone acetate for ≥6 months (particularly in athletes) 2

Proper DXA Technique

Scan Sites

• Always scan both lumbar spine (L1-L4) and bilateral hips (total hip and femoral neck) to capture discordance, which occurs in up to 30% of patients. 2, 3
• Never limit scanning to a single site, as this misses up to 30% of osteoporosis cases. 2

Vertebral Fracture Assessment (VFA)

Include VFA during the same DXA session when the patient meets any of these criteria: 1, 2, 3

• T-score <-1.0 AND age ≥70 years (women) or ≥80 years (men)
• T-score <-1.0 **AND** historical height loss >4 cm
• T-score <-1.0 AND self-reported prior vertebral fracture
• T-score <-1.0 AND glucocorticoid therapy ≥5 mg prednisone daily for ≥3 months

VFA identifies asymptomatic vertebral compression fractures in 20-30% of high-risk patients, and these fractures markedly raise future fracture risk independent of BMD. 2

Repeat Screening Intervals

Normal BMD or Mild Osteopenia

• Repeat DXA in 2-3 years for patients with normal bone density or T-score >-2.0. 1, 2, 3
• Evidence shows that repeating BMD measurement after 8 years is not more predictive of fracture risk than the original measurement in women with normal baseline BMD. 2
• The transition to osteoporosis takes approximately 17 years for women with normal baseline BMD versus 5 years for those with T-scores in the -1.50 to -1.99 range. 2

Osteoporosis or On Treatment

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

High-Risk for Accelerated Bone Loss

• Repeat DXA in 1-2 years for patients on glucocorticoid therapy or with spinal cord injury. 1, 3

Critical Timing Rules

• Never repeat DXA at intervals <1 year under any circumstances. 3
• Do not repeat DXA more frequently than every 2 years in patients with normal BMD, as testing precision limitations make shorter intervals unreliable. 2, 3

Score Interpretation

Use T-Scores For:

• All postmenopausal women regardless of age 2, 3
• Men ≥50 years 3

Use Z-Scores For:

• Premenopausal women 3
• Men <50 years 3
• Transgender individuals (using reference data conforming to gender identity) 1, 2

Common Pitfalls to Avoid

• Do NOT delay DXA in patients with chronic alcoholism until age 65/70—this secondary cause of osteoporosis justifies earlier screening regardless of age. 1, 3
• Do NOT attribute osteopenia seen on plain radiographs (e.g., shoulder X-ray) to normal aging—this is a red flag mandating formal DXA, as radiographs only reveal bone loss after 30-40% of mineral density is lost. 2
• Do NOT assume obesity provides adequate protection against osteoporosis when other major risk factors are present; obesity is actually protective but does not negate other risks. 1
• Do NOT use Z-scores for diagnosis in postmenopausal women—T-scores remain the standard. 2
• Do NOT omit VFA to save time in eligible patients—the additional radiation dose is minimal (~3 µSv) and diagnostic yield is clinically significant. 2
• Do NOT overlook comprehensive vitamin D and calcium supplementation in alcoholic patients, as malabsorption and dietary deficiency are nearly universal. 1