Z-score comparability of bone mineral density reference databases for children

Area of Science:

• Pediatric endocrinology
• Medical imaging
• Bone densitometry

Background:

• Dual-energy x-ray absorptiometry (DXA) is crucial for assessing bone mineral density (BMD) in children.
• Variability in pediatric DXA reference databases raises concerns about diagnostic consistency.

Purpose of the Study:

• To evaluate the comparability of BMD Z-scores derived from different Hologic DXA databases in pediatric patients.
• To determine if these databases are interchangeable for clinical application.

Main Methods:

• Analysis of 2027 BMD scans from Hologic QDR-4500A machines.
• Calculation and comparison of age- and sex-specific BMD Z-scores using six Hologic databases for lumbar spine (LS) and total body (TB) in children aged 8-17 years.

Main Results:

• BMD Z-scores showed high correlation but significant differences across databases (P < 0.001).
• Interdatabase Z-score variations reached up to 1.0 in total body measurements.
• The prevalence of low BMD for age (-2 or below) varied significantly, impacting diagnostic rates.

Conclusions:

• Clinically significant differences exist between Hologic DXA databases, posing a risk of misdiagnosis in pediatric BMD assessment.
• Utilizing model-, brand-, and software-specific reference curves is ideal for accurate Z-score calculation.
• The study highlights limitations of DXA in detecting all aspects of bone health in children.