Relationship between indices of adiposity obtained by peripheral quantitative computed tomography and dual-energy X-ray absorptiometry in pre-pubertal children

Background/Aim: The study investigated the relationship between indices of adiposity measured by peripheral quantitative computed tomography (pQCT) and dual-energy X-ray absorptiometry (DXA) in pre-pubertal children. Subjects and methods: DXA-derived per cent body fat (%BF) was measured in 284 boys and 288 girls, aged 7-10 years. Cross-sections of the forearm (n = 427) and lower leg (n = 560) were obtained by pQCT to measure total cross-sectional area of the limb (Total CSA), Muscle CSA, Fat CSA, % Fat CSA (Fat CSA/Total CSA x 100) and muscle density. Results: Peripheral QCT-derived % Fat CSA in the forearm and lower leg correlated strongly with DXA-derived % BF (r = 0.83-0.89, p<0.01) in both boys and girls. However, forearm and lower leg % Fat CSA were higher than whole body % BF by 5% and 10%, respectively. A better prediction of whole-body % BF was achieved by including % Fat CSA, muscle density and height into a hierarchical regression model. Using sex-specific regression equations, 87.7% of the boys and 83.7% of the girls had a predicted % BF within 3% units of the % BF obtained by DXA. Conclusion: In pre-pubertal children, pQCT measures of adiposity are strongly associated with whole-body per cent body fat. This reproducible method could be an alternative technique to estimate body composition in this population.