This retrospective observational study will examine bone mineral density measurements and their metabolic and clinical determinants in adults aged 40 years and older. Existing medical records of approximately 300 patients who underwent dual-energy X-ray absorptiometry (DXA) of the lumbar spine and femoral neck will be reviewed. The researchers will examine the relationships between DXA measurements and available clinical and laboratory findings. Differences between lumbar spine and femoral neck T-scores, bone mineral density discordance, fracture history, and FRAX fracture risk will also be evaluated. No additional examination, laboratory test, treatment, or intervention will be performed as part of the study.
Background: Bone mineral density measured at the lumbar spine and femoral neck may differ because these regions have different bone structures and may be affected differently by aging, metabolic factors, and degenerative changes. These differences may influence the diagnosis of osteoporosis and the assessment of fracture risk. Objective: This study aims to investigate the metabolic and clinical factors associated with bone mineral density parameters measured by DXA. It will also evaluate lumbar spine-femoral neck T-score differences, bone mineral density discordance, fragility fractures, and FRAX fracture risk. Method: This retrospective observational study will include adults aged 40 years and older who underwent DXA examination of the lumbar spine and femoral neck. Existing hospital records, DXA results, laboratory findings, and clinical information will be reviewed. The study will examine lumbar vertebral and femoral neck T-scores, the T-score difference between these regions, and concordant or discordant bone mineral density categories. Available metabolic and clinical variables will be analyzed. Previous and newly recorded fragility fractures and FRAX risk estimates will also be evaluated. No new tests or interventions will be performed.
Study Type
OBSERVATIONAL
Enrollment
750
Mardin Training and Research Hospital
Mardin, Turkey (Türkiye)
Lumbar Spine-Femoral Neck T-Score Gradient
The lumbar spine-femoral neck T-score gradient will be calculated by subtracting the femoral neck T-score from the mean lumbar spine T-score obtained from eligible L1-L4 vertebrae. T-scores represent the number of standard deviations by which bone mineral density differs from the young-adult reference mean. T-scores and the calculated gradient do not have predefined minimum or maximum values. Higher positive gradient values indicate a relatively higher lumbar spine T-score compared with the femoral neck, while more negative values indicate a relatively lower lumbar spine T-score. The relationships between the gradient and metabolic and clinical variables will be evaluated.
Time frame: Baseline
Lumbar Spine-Femoral Neck Bone Mineral Density Discordance
Lumbar spine and femoral neck T-scores will be classified as normal (T-score ≥ -1.0), osteopenic (T-score \< -1.0 and \> -2.5), or osteoporotic (T-score ≤ -2.5). Participants will be classified as concordant when the lumbar spine and femoral neck are in the same diagnostic category and discordant when they are in different diagnostic categories. This is a categorical outcome reported as concordant or discordant and is not a numerical scale; therefore, it has no minimum or maximum score, and higher values do not represent a better or worse outcome.
Time frame: Baseline
Prevalent Fragility Fracture
The presence of a fragility fracture before or at the time of the index DXA examination will be identified from medical records, radiology reports, and available imaging. Vertebral, hip, distal radius, and proximal humerus fractures caused by low-energy trauma will be included.
Time frame: Before or at the index DXA examination
Incident Fragility Fracture
New fragility fractures occurring after the index DXA examination will be identified from medical records, radiology reports, and available imaging. Vertebral, hip, distal radius, and proximal humerus fractures caused by low-energy trauma will be included.
Time frame: From the index DXA examination to the date of record review, up to 10 years
FRAX 10-Year Major Osteoporotic Fracture Probability
The 10-year probability of a major osteoporotic fracture will be calculated using the Turkey-specific Fracture Risk Assessment Tool model, with femoral neck bone mineral density and available clinical risk factors. Major osteoporotic fracture includes clinical vertebral, hip, forearm, or proximal humerus fracture. The probability is reported from 0% to 100%, with higher percentages indicating a greater 10-year risk of major osteoporotic fracture.
Time frame: Baseline
FRAX 10-Year Hip Fracture Probability
The 10-year probability of hip fracture will be calculated using the Turkey-specific Fracture Risk Assessment Tool model, with femoral neck bone mineral density and available clinical risk factors. The probability is reported from 0% to 100%, with higher percentages indicating a greater 10-year risk of hip fracture.
Time frame: Baseline
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