Weight-for-height values and limb anthropometric composition of tube-fed children with quadriplegic cerebral palsy.

OBJECTIVE Research has shown that growth retardation among children with quadriplegic cerebral palsy (CP) is often attributed to feeding dysfunction and malnutrition. The study compared weight-for-height values and limb anthropometric composition of nasogastric and gastrostomy tube-fed children with quadriplegic CP with those of orally fed children with quadriplegic CP and normal children, to examine the plausible effects of tube feeding on weight-for-height, fat, and muscle values for children with quadriplegic CP. METHODS Triceps, anterior mid-thigh, and medial calf skinfold thicknesses and the corresponding circumferences of the right or less affected side were measured. The subjects consisted of 119 normal children and 62 orally fed and 48 tube-fed children with quadriplegic CP. Body weight and height were recorded. For children with CP whose height could not be measured, height was estimated from the ulna length. Weight-for-height z scores, limb skinfold thicknesses, fat areas, skinfold-corrected muscle girths, and muscle areas of the children were compared. RESULTS Tube-fed children with CP had normal mean weight-for-height z scores. Weight-for-height z scores of the orally fed children with CP were significantly below those of normal children and tube-fed children with CP. For children with CP, whereas triceps skinfold thickness seemed to predict the mid-upper arm fat area correctly, leg skinfold thicknesses seemed to overestimate the corresponding fat areas. Stepwise multiple regression analysis showed that triceps skinfold thicknesses had good correlation (r = 0.86) and the presence of CP had nonsignificant correlation with mid-upper arm fat areas. Multiple regression analysis of fat areas with skinfold thicknesses and the presence of CP, however, showed that CP was correlated negatively (partial correlation of CP: thigh, -0.45; calf, -0.53) with thigh and calf fat areas. Although skinfold-corrected mid-upper arm muscle girths of children with CP were quite similar to those of normal children, leg muscle girths were much reduced for both orally fed and tube-fed children with CP. The apparent thickening of leg skinfold thicknesses among children with CP probably was attributable to disproportional leg muscle wasting, with resulting reduced internal circumference of the subcutaneous fat layer. For tube-fed children with CP, skinfold thicknesses and fat areas were increased significantly, although their leg skinfold-corrected muscle girths and areas remained reduced. CONCLUSIONS Skinfold thickness may overestimate the fat area in the affected limb with significant muscle wasting for children with CP. The condition was particularly obvious in the leg, where muscle wasting was prominent. Because leg muscles represent approximately one quarter of the normal body weight, low weight-for-height values among children with CP can be caused by leg muscle wasting attributable to disuse atrophy, which is unlikely to be correctable with tube feeding. Tube feeding may improve body weight mainly through fat deposition.