Anthropometric assessment of muscularity during growth: estimating fat-free mass with 2 skinfold-thickness measurements is superior to measuring midupper arm muscle area in healthy prepubertal children.
BACKGROUND
Anthropometric measurements are widely used to determine body composition, especially in children.


OBJECTIVE
Our aim was to compare 2 of the simplest anthropometry-based equations available for determining nutritional status and muscularity in children and adolescents, examined in relation to other methodologically independent muscle variables.


METHODS
Midupper arm muscle area (UAMA) and fat-free mass (FFM) according to the equations of Slaughter et al (Hum Biol 1988;60:709-23), as well as separate biochemical, physical, and radiologic muscle variables, were determined cross-sectionally in 91 males and 91 females aged 6-18 y. The ability of UAMA and FFM to estimate muscularity, as measured by 24-h creatinine excretion, grip force, and peripheral quantitative computer tomography analysis of forearm muscle, was compared after dividing the study population into prepubertal and pubertal groups.


RESULTS
Before puberty, correlations of all 3 muscularity variables were higher with FFM than with UAMA in both males and females. Multiple regression analyses confirmed FFM to be the predominant predictor, with partial R(2) >/= 0.68 (P < 0.001). However, in puberty, FFM did not consistently show this major influence. Only before puberty did FFM provide a significantly better fit (P < 0.05) than did UAMA for 2 of the 3 muscularity variables in each sex.


CONCLUSIONS
The FFM estimate proved to be the better predictor for muscularity in healthy prepubertal children and is on a par with UAMA during puberty. FFM can be recommended as a simple anthropometric method to assess nutritional status before puberty, at least in healthy children.
Department of Nutrition and Health, Research Institute of Child Nutrition, Dortmund, Germany. boye@fke-do.de
Kai R
KR
Boye
Triantafillia
T
Dimitriou
Friedrich
F
Manz
Eckhard
E
Schoenau
Christina
C
Neu
Stefan
S
Wudy
Thomas
T
Remer
D000293:Adolescent; D000375:Aging; D000886:Anthropometry; D001823:Body Composition; D002648:Child; D003404:Creatinine / Q000652:urine; D005260:Female; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000033:anatomy & histology* / Q000254:growth & development; D009752:Nutritional Status; D011627:Puberty; D012044:Regression Analysis; D012885:Skinfold Thickness
D003404:Creatinine