Assessment of body composition in children with cerebral palsy: A cross-sectional study in Norway

Abstract

Aim: The assessment of growth and body composition is challenging in children with cerebral palsy (CP). The aim of this study was to compare clinical assessments of body composition with measurements obtained using dual-energy X-ray absorptiometry (DXA) in this population. Method: Knee height, weight, and triceps and subscapular skinfold thickness (SFT) were measured in 47 children with CP (age range 8-18y; 18 females, 29 males). Height was estimated from knee height, and used to calculate body mass index (BMI). Using SFT measurements, body fat percentage was calculated by standard ('Slaughter') and CP-modified ('Gurka') equations and compared with results obtained using DXA. Results: Children with severe gross motor function impairments (Gross Motor Function Classification System [GMFCS] level III or IV) exhibited stunted growth and had higher fat percentages and lower lean body mass than children classified in GMFCS level I or II. In 10 children classified as 'thin' according to their BMI (five of whom were assigned thinness grade of 2 or lower), percentage of body fat, as determined by DXA, was normal or high. The Slaughter equations significantly underestimated body fat percentages, whereas the precision of the CP-modified Gurka equations was excellent. Interpretation: In this study, children with CP and severe motor impairments displayed stunted growth, but were not undernourished. Relying solely upon BMIs may be misleading in children with CP. Therefore, clinicians should be encouraged to measure SFT and to calculate body fat percentages using the CP-modified version of the Slaughter equation. What this paper adds: Children with cerebral palsy (CP) who are classified as thin based on body mass index (BMI) calculations may have adequate or excess body fat. BMI, weight z-score, and skinfold thickness alone may be misleading in the assessment of nutritional status in children with CP. Equations based upon skinfold thickness measurements and modified for use in children with CP can reliably estimate percentage body fat.