Total body protein mass: validation of total body potassium prediction model in children and adolescents.
Protein is an important body component for monitoring growth, development, and nutritional status. We previously developed a total body potassium (TBK, in mmol) and bone mineral (Mo, in kg) model for predicting total body protein (TBPro, in kg) in adults (TBPro = 0.00252 x TBK + 0.732 x Mo). However, the applicability of the TBK-Mo model for children is unknown. The study aims were to develop a TBK-independent 6-component (6-C) TBPro approach as the criterion, and then to validate the TBK-Mo model in children. The following measurements were made in adolescents and children (n = 62, 38 boys and 24 girls, aged 5-17 y): body weight (BW, in kg), body volume (BV, in liters) by air displacement plethysmography, total body water (TBW, in kg) by 2H2O dilution, Mo by dual-energy X-ray absorptiometry, and TBK by whole-body counting. A 6-C model was derived as TBPro = 2.922 x BW - 0.301 x TBW - 2.039 x Mo - 2.632 x BV. The TBPro estimates did not differ between the 6-C and TBK-Mo models (mean +/- SD, 0.20 +/- 0.86 kg). There was a significant correlation between TBPro by the 6-C and TBK-Mo models (r = 0.94, P < 0.001). Bland-Altman analysis indicated that the differences between TBPro by 6-C and TBK-Mo models were not significantly correlated with the mean TBPro estimates by the 2 models (r = 0.032, P > 0.05). The TBK-Mo model can thus be used to estimate TBPro in healthy adults, adolescents, and children > 5 y old.
Obesity Research Center, St. Luke's-Roosevelt Hospital, Columbia University College of Physicians and Surgeons, New York, NY, USA. ZW28@Columbia.edu
ZiMian
Z
Wang
Stanley
S
Heshka
Jack
J
Wang
Steven B
SB
Heymsfield
D015502:Absorptiometry, Photon; D000273:Adipose Tissue; D000293:Adolescent; D001823:Body Composition; D015992:Body Mass Index; D001834:Body Water; D001835:Body Weight; D015519:Bone Density; D002648:Child; D002675:Child, Preschool; D003903:Deuterium; D005260:Female; D006801:Humans; D008297:Male; D008954:Models, Biological; D010991:Plethysmography; D011188:Potassium / Q000032:analysis*; D011506:Proteins / Q000032:analysis*
D011506:Proteins; D003903:Deuterium; D011188:Potassium