DEXA Scan
Dual-energy X-ray absorptiometry — the gold standard for measuring bone density, body composition, and visceral fat.
Optimal Range
T-score > -1.0 (bone) · ALMI and visceral fat within range
Risk-Stratified Targets
| Population / Context | Target |
|---|---|
| Bone density — normal | T-score > -1.0 |
| Bone density — osteopeniaBegin prevention strategies | T-score -1.0 to -2.5 |
| Bone density — osteoporosisTreatment indicated; fracture risk significantly elevated | T-score < -2.5 |
| ALMI — normal (men) | > 7.0 kg/m² |
| ALMI — normal (women) | > 5.4 kg/m² |
| ALMI — sarcopenicPrioritize resistance training and protein intake | Below sex-specific cutoffs |
Why It Matters
DEXA provides three critical longevity metrics in one scan: bone density (osteoporosis risk), lean muscle mass (sarcopenia risk), and visceral fat (metabolic risk). Sarcopenia and osteoporosis are leading drivers of disability and mortality in aging.
Understanding DEXA Scan
DEXA (dual-energy X-ray absorptiometry) is unique among imaging tests in that it provides three distinct and critically important longevity metrics in a single, low-radiation scan: bone mineral density, body composition (lean mass vs. fat mass distribution), and visceral adipose tissue (VAT) quantification.
Bone density is expressed as a T-score — the number of standard deviations your bone density falls above or below the average healthy young adult. A T-score above -1.0 is normal, -1.0 to -2.5 indicates osteopenia (bone thinning), and below -2.5 indicates osteoporosis. Osteoporotic fractures — particularly hip fractures — are among the leading causes of disability and death in older adults, with 1-year mortality after hip fracture approaching 20–30%. Yet bone loss is often entirely silent until a fracture occurs, making screening essential.
The body composition data from DEXA is equally valuable for longevity. The appendicular lean mass index (ALMI — lean mass of arms and legs divided by height squared) is the standard measure for diagnosing sarcopenia (age-related muscle loss). Sarcopenia is strongly associated with frailty, falls, metabolic dysfunction, and mortality. Visceral adipose tissue quantification identifies deep abdominal fat surrounding the organs — the most metabolically dangerous fat depot, strongly correlated with insulin resistance, cardiovascular disease, and systemic inflammation. Together, these three metrics provide a comprehensive structural assessment of your aging trajectory.