Bone Mineral Density Interpretation

Diagnostic Criteria and T-Score Classification

The American College of Radiology recommends that osteoporosis is diagnosed when the T-score is ≤-2.5 at the hip or lumbar spine, representing bone density 2.5 standard deviations or more below the mean for young healthy White women, which has become the reference standard for all racial and ethnic groups and both sexes 1, 2
The World Health Organization defines osteopenia (low bone mass) as a T-score between -1.0 and -2.5, according to the Journal of the American College of Radiology 3
Normal bone density is defined as a T-score ≥-1.0, as stated by the Journal of the American College of Radiology 4
T-scores compare the patient's BMD to a young adult reference population and are used for postmenopausal women and men ≥50 years, as recommended by the Journal of the American College of Radiology 4, 5

The Journal of the American College of Radiology recommends using T-scores for diagnosis in postmenopausal women and men ≥50 years 4, 6
The World Health Organization criteria apply to postmenopausal women and men ≥50 years, as stated by the Journal of the American College of Radiology 5, 6
A T-score ≤-2.5 confirms osteoporosis and warrants treatment consideration, according to JAMA 1, 2

The Journal of the American College of Radiology recommends that DXA measurement should include the lumbar spine (L1-L4), total hip, and femoral neck as the gold standard for diagnosis 4
The American College of Radiology suggests excluding individual vertebral levels with spuriously elevated BMD due to degenerative changes, fractures, or facet arthropathy 4, 6

JAMA states that BMD alone does not fully capture fracture risk across different populations, as racial and ethnic groups show varying fracture incidence despite similar BMD values 1, 2
African American women have higher average BMD than White women at any given age and lower fracture incidence, as reported by JAMA 1

JAMA recommends using FRAX or another clinical risk assessment tool to determine treatment thresholds for postmenopausal women <65 years with osteopenia (T-score -1.0 to -2.5) 1, 2
The American College of Radiology suggests initiating pharmacologic treatment when 10-year probability of major osteoporotic fracture is ≥20% or 10-year probability of hip fracture is ≥3% 3

The Journal of the American College of Radiology warns that degenerative spondylosis and facet osteoarthritis can spuriously elevate lumbar spine BMD, leading to underdiagnosis of osteoporosis 4, 6
The American College of Radiology recommends never using T-scores or applying WHO criteria to premenopausal women or men <50 years 5, 6

The Annals of Internal Medicine states that a minimum 2-year interval between DXA scans is required to reliably detect true bone density changes due to precision limitations 7
The Journal of the American College of Radiology suggests shortening rescreening intervals for new glucocorticoid therapy or other medications causing bone loss, incident fragility fracture, or development of conditions associated with secondary bone loss 8

The American College of Radiology recommends initiating oral bisphosphonates as first-line therapy for patients with T-score ≤-2.5 3, 9
The American College of Radiology suggests considering anabolic therapy (teriparatide, abaloparatide, or romosozumab) as initial treatment for very high-risk patients (recent vertebral fracture, hip fracture with T-score ≤-2.5, multiple prevalent fractures) 9