Validity assessment of a portable bioimpedance scale to estimate body fat percentage in White and African-American children and adolescents

Objective: The objective of the study was to determine accuracy of the Tanita SC-240 body composition analyser to measure paediatric percent body fat (%BF). Methods: Eighty-nine African-American and white 5-18-year-olds participated in this study. %BF was estimated by dual-energy X-ray absorptiometry (DXA) and by the Tanita SC-240. Results: Overall %BF was 33.5 - 10.5% (Tanita SC-240) vs. 34.5 - 8.7% (DXA). There was no significant difference between the two measures (P = 0.52, average error = -1.0%, average absolute error = 3.9%). The Tanita mean %BF estimates significantly differed from the DXA mean %BF in white boys (P = 0.001, Cohen's d = 0.40) and white girls (P = 0.006, Cohen's d = 0.48), but differences were of small effect. No differences in %BF estimates were found for African-American boys or girls. Conclusions: In this sample, the Tanita SC-240 demonstrated acceptable accuracy for estimating %BF when compared with DXA, supporting its use in field studies.