Relationship between bioelectric impedance, body muscularity and body adiposity in young children

We examined the relationships between bioelectric impedance (BI), body adiposity and body muscularity in a sample of 1540 Italian children aged from 6 to 12 years. BI and the impedance index (height(2)/BI) were found to increase with increasing levels of body adiposity (as determined by arm fat area and by the sum of four skinfolds according to Durnin & Womerseley) and body muscularity (as determined by arm muscle area and circumference), respectively. Based on the comparison with body mass index, relative weight and triceps skinfold, BI was shown to be a better index of body adiposity than height(2)/BI. However, the impedance index was a better index of body muscularity than BI. We conclude that BI and height(2)/BI have the potential to be employed as indexes of adiposity and muscularity, respectively, in childhood. For this reason, we have provided percentile values for BI and height(2)/BI which may be used in italian children from 6 to 12 years of age.