Anthropometric measures: poor predictors of body fat in children with moderate to severe cerebral palsy

AIM This purpose of our study was to assess and compare anthropometric measures of adiposity and direct measurement of percentage body fat by dual emission X-ray absorptiometry (DXA) in children with cerebral palsy (CP). We also compared our results in children with CP with results from a national sample of typically developing children from the National Health and Nutrition Examination Survey. METHOD Anthropometry and DXA were obtained from 58 participants with CP (25 females, 33 males; Gross Motor Function Classification System levels III-V; mean age 13y 1mo [SD 3y], range 8-18y). Height was estimated from knee height, which was measured with knee height calipers; weight was measured on a sitting scale. The relation between percentage body fat measured by DXA and z-scores of each of the anthropometric measures (body mass index, mid-upper arm circumference, triceps skinfold, and mid-upper arm fat area) was assessed by linear models. Agreement analysis was performed to assess the ability of each anthropometric measure to predict percentage body fat by DXA. RESULTS None of the anthropometric measures were adequately associated with percentage body fat by DXA. All anthropometric methods tended to underestimate percentage body fat in children with CP. INTERPRETATION Single anthropometric measures do not perform well in predicting percentage body fat in children with or without CP. Further work is needed to develop clinically useful and simple assessments that will predict percentage body fat and to determine the relation between percentage body fat and health to guide clinical practice.