Individualized evaluation of lumbar bone mineral density in children with cerebral palsy

Lumbar spine bone mineral density (LS-BMD) assessed by dual-energy X-ray absorptiometry (DXA) is used in children with cerebral palsy (CP) to evaluate bone health. LS-BMD results in children with CP are influenced significantly by their height, BMI, and mobility level. An adjustment for these parameters might improve the clinical significance of the method.

DXA evaluation is considered useful in children with CP to assess bone health. For this purpose, LS-BMD is often used. The aim of the study was to estimate the effect of height, BMI, and reduced mobility level of children with CP on LS-BMD and to develop a method to adjust individual results of LS-BMD for these factors.

We conducted a monocentric retrospective analysis of data collected in children and adolescents with CP, who participated in a rehabilitation program and had no history of recurrent fractures. The DXA scan was part of the routine examination for participants older than 4 years of age. The relationship between height and BMI for age Z-scores and age-adjusted LS-BMD Z-scores was analyzed.

LS-DXA scans of 500 children and adolescents with CP (Gross Motor Function Classification System levels I-V) were included in the statistical analysis (217 female). The mean age was 9.4 years (± 3.7 years). Children with moderate to severe CP had significantly (p < 0.001) lower LS-BMD Z-scores than children with mild CP. We provided nomograms to adjust individual LS-BMD results to their height, BMI, and mobility level.

LS-BMD results in children with CP were influenced significantly by their height, BMI, and mobility level. An adjustment of the LS-BMD results to height, BMI, and mobility level might improve the clinical significance of an individual result.