DEXA Scan Recommendations for Men with Hypogonadism
Men with hypogonadism should undergo DEXA scanning at age 18 years or older, regardless of age, as hypogonadism is an established independent risk factor for secondary osteoporosis that warrants immediate bone density assessment.
Primary Recommendation
- Hypogonadal men older than 18 years of age should receive DEXA screening of the lumbar spine and bilateral hips 1.
- This recommendation applies to all forms of hypogonadism, including congenital hypogonadotropic hypogonadism, primary testicular failure, and surgically or chemotherapeutically induced castration 1.
- The age threshold of 18 years represents the point at which adult bone density assessment becomes appropriate, not a recommendation to delay screening 1.
Clinical Rationale
- Hypogonadism causes both trabecular and cortical osteoporosis through multiple mechanisms, including reduced plasma 1,25-dihydroxyvitamin D, calcium malabsorption, and decreased bone formation 2.
- Men with hypogonadism demonstrate altered trabecular architecture with reduced trabecular number, which differs from age-related bone loss patterns 2.
- The prevalence of osteopenia/osteoporosis in hypogonadal men is extremely high, with 83% showing lumbar osteopenia/osteoporosis and 61% showing femoral osteopenia/osteoporosis at initial assessment 3.
Diagnostic Approach
- Z-scores (not T-scores) should be reported for men under age 50, as WHO criteria for osteoporosis do not apply to this age group 1.
- Z-scores of -2.0 or less are considered below the expected age range and indicate clinically significant bone loss 1.
- For men 50 years and older, standard T-score criteria apply, with T-score ≤-2.5 indicating osteoporosis 4.
Scanning Protocol
- Standard DEXA should include lumbar spine (L1-L4) and bilateral hips (total hip and femoral neck) 4, 5.
- Vertebral fracture assessment (VFA) should be performed during the same session if the patient has additional risk factors such as height loss >4 cm, prior fractures, or glucocorticoid exposure 1, 4.
Follow-Up Monitoring
- For hypogonadal men at high risk for accelerated bone loss, repeat DEXA every 1-2 years 1.
- For those with stable bone density on testosterone replacement therapy, monitoring intervals of 2 years are appropriate 1.
- Men who interrupt testosterone replacement therapy require closer monitoring, as bone density clearly decreases with treatment discontinuation 3.
Treatment Considerations
- Testosterone replacement therapy in treatment-naive hypogonadal men produces substantial improvements in bone density, with lumbar T-score increases of 2.19 and femoral increases of 1.47 3.
- However, even with prolonged testosterone therapy, 61% of patients maintain lumbar osteopenia/osteoporosis and 48% maintain femoral osteopenia/osteoporosis 3.
- Testosterone therapy increases plasma 1,25-dihydroxyvitamin D, improves calcium absorption, and enhances bone formation 2.
Critical Pitfalls to Avoid
- Do not delay DEXA screening in hypogonadal men until age 50 or 70, as the presence of hypogonadism justifies immediate screening regardless of age 1, 4.
- Do not assume that testosterone replacement therapy alone will normalize bone density; most patients require additional interventions including calcium and vitamin D supplementation 6, 3.
- Do not overlook comprehensive evaluation for other secondary causes of osteoporosis, as hypogonadal men may have multiple contributing factors 1, 7.
- Do not use T-scores for men under age 50, as this leads to misclassification and inappropriate treatment decisions 1.
Comprehensive Metabolic Workup
- All hypogonadal men with low bone density should undergo evaluation including serum calcium, phosphate, alkaline phosphatase, 25-hydroxyvitamin D levels, and parathyroid hormone if calcium abnormalities are detected 8.
- Assessment should include testosterone levels, luteinizing hormone, follicle-stimulating hormone, and evaluation for other endocrine disorders affecting bone metabolism 7.