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

J Kocks1, K Ward, Z Mughal

  • 1Department of Pediatrics, Medical University Innsbruck, Innsbruck, Austria.

The Journal of Clinical Endocrinology and Metabolism
|July 30, 2010
PubMed

Insights

Pediatric bone mineral density (BMD) Z-scores from different Hologic dual-energy x-ray absorptiometry (DXA) databases show significant differences, potentially leading to misdiagnosis in children. Using specific reference curves is recommended for accurate BMD assessment.

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.
Abstract

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