Mathematical model for body fat percentage of children with cerebral palsy

Abstract Introduction The aim of this study was to develop a specific mathematical model to estimate the body fat percentage (BF%) of children with cerebral palsy, based on a Brazilian population of patients with this condition. Method This is a descriptive cross-sectional study. The study included 63 Caucasian children with cerebral palsy, both males and females, aged between three and ten-years-old. Participants were assessed for functional motor impairment using the Gross Motor Function Classification System (GMFCS), dual energy x-ray absorptiometry (DXA) and skinfold thickness. Total body mass (TBM) and skinfolds thickness from: triceps (Tr), biceps (Bi), Suprailiac (Si), medium thigh (Th), abdominal (Ab), medial calf (Ca) and subscapular (Se) were collected. Fat mass (FM) was estimated by dual energy x-ray absorptiometry (gold standard). Results The model was built from multivariate linear regression; FM was set as a dependent variable and other anthropometric variables, age and sex, were set as independent variables. The final model was established as F%=((0.433xTBM + 0.063xTh + 0.167xSi - 6.768) ÷ TBM) × 100, the R2 value was 0.950, R2adjusted=0.948 and the standard error of estimate was 1.039 kg. Conclusion This method was shown to be valid to estimate body fat percentage of children with cerebral palsy. Also, the measurement of skinfolds on both sides of the body showed good results in this modelling.