At what age should Dual-Energy X-ray Absorptiometry (DEXA) screens be started for individuals with average and high risk profiles for osteoporosis?

DEXA Screening Age Recommendations

All women should begin routine DEXA screening at age 65 years, and all men should begin at age 70 years, regardless of risk factors. 1, 2, 3

Standard Screening Ages for Average-Risk Individuals

• Women aged 65 years and older require routine DEXA screening with no additional risk factors needed. 1, 2, 3, 4

• Men aged 70 years and older require routine DEXA screening regardless of risk factors. 1, 2, 3, 4

• Routine screening is NOT recommended for women younger than 65 or men younger than 70 who lack risk factors, as this exposes patients to unnecessary radiation and costs without clinical benefit. 2, 3, 4

Earlier Screening for High-Risk Individuals

Postmenopausal women under 65 and men under 70 should undergo DEXA screening only when specific risk factors are present:

Major Risk Factors Warranting Earlier Screening

• Previous fragility fracture at any age (any low-trauma fracture occurring from standing height or less) 2, 3, 4

• Long-term glucocorticoid therapy (equivalent to ≥5 mg prednisone daily for ≥3 months) 2, 3, 4

• Parental history of hip fracture 3

• Body weight less than 127 pounds or low BMI (<20-25 kg/m²) 3, 4

• Early menopause (before age 45) or surgically/chemotherapeutically induced castration 3, 4

Medical Conditions Requiring Earlier Screening

• Hypogonadism in men or premenopausal women 3, 4

• Androgen deprivation therapy for prostate cancer 2, 3, 4

• Chronic alcoholism (impairs calcium absorption, causes vitamin D deficiency, and has direct toxic effects on osteoblasts) 4

• Hyperparathyroidism, chronic renal failure, or rheumatoid arthritis 2, 3, 4

• Eating disorders or malabsorption syndromes 3

• Spinal cord injury (screen as soon as medically stable) 2, 3, 4

High-Risk Medications Requiring Earlier Screening

• Aromatase inhibitor therapy 3

• Anticonvulsant drugs or chronic heparin therapy 3

• Any medication associated with accelerated bone loss 2, 4

Fracture Risk Assessment Threshold

• Postmenopausal women under 65 with a 10-year major osteoporotic fracture risk ≥9.3% as calculated by FRAX should undergo DEXA screening. 1, 3, 4

• This 9.3% threshold represents the fracture risk of a 65-year-old white woman with no additional risk factors. 2

• The FRAX threshold of 9.3% has limitations—it demonstrates only 37% sensitivity for detecting osteoporosis in women ages 50-64, though it remains the recommended screening tool. 5

Screening Intervals After Initial DEXA

• For individuals with normal bone density (T-score ≥-1.0) or mild osteopenia, repeat DEXA in 2-3 years. 2, 3, 4

• For individuals with osteoporosis (T-score ≤-2.5) or on treatment, repeat DEXA in 1-2 years to monitor treatment effectiveness. 2, 3, 4

• For high-risk individuals (glucocorticoid therapy, spinal cord injury), repeat DEXA in 1-2 years. 3, 4

• Never repeat DEXA at intervals less than 1 year under any circumstances, as testing precision limitations make shorter intervals unreliable. 2, 3

• For women with normal baseline BMD and bone loss <1% per year, the change in BMD is unlikely to exceed measurement variability in less than 3 years, and BMD is unlikely to drop to treatment thresholds for at least 16 years. 6

Critical Pitfalls to Avoid

• Do not delay screening in patients with chronic alcoholism, early menopause, or glucocorticoid use—these conditions justify earlier screening regardless of age. 3, 4

• Do not screen women under 65 or men under 70 without documented risk factors, as this represents inappropriate use of resources. 2, 3, 4

• Do not repeat DEXA scans more frequently than every 2 years in patients with normal BMD, as the rate of bone loss in untreated individuals is generally less than 1% per year. 6

• Do not assume obesity provides adequate protection against osteoporosis when other major risk factors are present—while higher body weight is protective, it does not eliminate risk in the presence of secondary causes. 4

• Do not overlook men—they account for 24% of hip fractures and 21% of wrist fractures but receive only 10% of BMD tests and half the treatment rate of women after fracture. 6

Scan Technique

• Scan both lumbar spine and bilateral hips when feasible. 3, 6

• Use T-scores for all postmenopausal women regardless of age and for men aged 50 and older. 3

• Use Z-scores for premenopausal women and men under 50. 3

• **Consider Vertebral Fracture Assessment (VFA) during the same session for patients with T-score <-1.0 and additional risk factors** (women ≥70 years, men ≥80 years, historical height loss >4 cm, prior vertebral fracture, or glucocorticoid therapy ≥5 mg prednisone daily for ≥3 months). 2, 3