BACKGROUND No studies have directly measured body protein or validated skinfold-thickness anthropometry and dual-energy X-ray absorptiometry (DXA) to assess body protein in children with spastic quadriplegic cerebral palsy (SQCP). OBJECTIVE We aimed to measure and evaluate body protein and to determine whether skinfold-thickness anthropometry and DXA can predict body protein in children with SQCP. DESIGN This was a cross-sectional study of 59 children (22 girls, 37 boys) aged 3.9-19.5 y with SQCP. The children underwent measurements of anthropometric indexes, lean tissue mass by DXA (LTM(DXA)), and total body protein by neutron activation analysis (TBP(NAA)). In addition, TBP was estimated from both skinfold-thickness anthropometry (TBP(SKIN)) and DXA (TBP(DXA)). The agreement of TBP(SKIN) and TBP(DXA) was tested against TBP(NAA) by using Bland and Altman plot analysis. RESULTS Height and weight SD scores (x +/- SD: -3.1 +/- 1.6 and -4.8 +/- 5.3, respectively) were significantly lower than reference data in the children with SQCP (P < 0.001). TBP(NAA) for age and height was low in the children with SQCP (P < 0.001): 56.1 +/- 17.3% and 81.5 +/- 15.7%, respectively, of the values predicted from control data. TBP(SKIN) and TBP(DXA) were both highly correlated with TBP(NAA): r = 0.90, P < 0.001, and r = 0.91, P < 0.001, respectively. Despite these significant correlations, agreement analyses showed wide variation of up to 33.3% of the mean for both methods. CONCLUSIONS Body protein in children with SQCP is significantly reduced for age and height. Skinfold anthropometry and DXA show wide variation in estimation of body protein compared with NAA in this group of children.

Muscle blood flow can be reduced in insulin-resistant states. The present study examined the importance of body fatness and insulin sensitivity as variables that may be associated with muscle oxygen supply. We studied 38 adolescents (22 males, 16 females; age 15.3-18.6 years; body mass index 17.7-34.7 kg/m(2)) and used near-IR spectroscopy to measure the muscle re-oxygenation rate after ischaemic finger flexion exercise. Total body fat content was estimated by bioelectrical impedance analysis, and insulin sensitivity was assessed by homoeostasis model assessment. Regional lipid compartments were also assessed for potential associations with muscle oxygen supply. Abdominal adiposity (visceral and subcutaneous) was assessed by magnetic resonance imaging, and soleus intramyocellular lipid levels were determined by magnetic resonance spectroscopy. Total body fat content ( r =0.67, P <0.001), abdominal subcutaneous fat area ( r =0.78, P <0.001), abdominal visceral fat area ( r =0.54, P <0.001) and intramyocellular lipid levels ( r =0.68, P <0.001) were significantly related to forearm re-oxygenation half-time. After adjusting for insulin sensitivity, both total body fat content ( r =0.395, P =0.02) and abdominal subcutaneous fat area ( r =0.543, P =0.001) remained positively associated with relatively reduced muscle oxygen supply in adolescent subjects. After adjusting for body fat content, abdominal subcutaneous fat area ( r =0. 511, P =0.002) was significantly associated with muscle oxygen supply. Thus muscle oxygen supply is associated with body fat content, and certain fat compartments may be more influential than others.