Preferable percentage body fat estimation equation for Japanese athletic children : comparison using Japanese and non-Japanese specific equations

Abstract

Objectives: To compare estimated percentage body fat (%BF) values from available equations and determine
the preferable equation to be used in athletic and non-athletic Japanese children and adolescents.
Methods: Body density (BD) of 250 non-athletic and 234 athletic boys and 292 non-athletic and 180 athletic
girls (less than 18 years old) was determined by the underwater weighing method (UWW) and %BF
estimated using the following equations: (1) Siri (Eq(Siri)), (2) Brozek et al. (Eq(Brozek)), (3) Lohman et al.
(Eq(Lohman84)), (4) age- and gender-specific Lohman (Eq(Lohman86)) and (5) Tobe et al. (Eq(Tobe)). Using %BF values
estimated from Japanese-specific Eq(Tobe) as the reference, estimated %BF values and estimation patterns
were compared. Also, using < 5% in boys and < 15% in girls as a minimum level for ‘essential lipids’ and
using the sum of two skinfolds developed for Japanese as criterion for obesity, likelihood of underestimation
and sensitivity/specificity using each equation were determined. --
Results: Estimated %BF from the tested equations were significantly different to each other (P<0.01).
Compared to Eq(Tobe), Eq(Brozek) and Eq(Lohman84) showed a considerable over- and underestimation in children
with low %BF. Also Eq(Lohman86) showed gender differences in estimation pattern which may be attributed to
ethnic differences in the timing of puberty. For athletic groups, proportions of underestimated individuals
reduces when using Eq(Siri). --
Conclusion: Although further confirmation is required, Eq(Tobe) may be the preferred choice for %BF estimation
in non-athletic Japanese children and Eq(Siri) for children who participate in regular physical training.