No differences in the body fat after violating core bioelectrical impedance measurement assumptions

• Published in: BMC public health Vol. 21; no. 1; p. 495
• Main Authors: Randhawa, Arshdeep K, Jamnik, Veronica, Fung, Michael D T, Fogel, Adam S, Kuk, Jennifer L
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 12.03.2021; BioMed Central; BMC
• Subjects: Adipose tissues; Age; BIA assumptions; Bioelectrical impedance; Bioelectricity; Bladder; BMI; Body composition; Body fat; Body mass; Body mass index; Body size; Body weight; Body weight loss; Dehydration; Demographic aspects; Diagnosis; Electric currents; Exercise; Food; Food intake; Health aspects; Hydration; Impedance; Impedance measurement; Impedance, Bioelectric; Laboratories; Measurement; Men; Obesity; Overweight; Physical fitness; Questionnaires; Reagents; Risk factors; Urine; Weight loss; Women; Canada; United States > US; Illinois; Obesity; BIA assumptions; Body fat; Impedance; Bioelectrical impedance; BMI
• ISSN: 1471-2458; 1471-2458
• DOI: 10.1186/s12889-021-10552-y

It is unclear to what degree acutely violating bioelectrical impedance analysis (BIA) measurement assumptions will alter the predicted percent fat mass (%FM) and whether this differs by sex or body mass index (BMI). %FM was assessed under control, dehydration, exercise, water, food intake and non-voided bladder conditions with three BIA devices (Tanita: BC-418, TBF-314, & Omron HBF-306CN) for men (n = 23, age: 24.0 ± 5.2 years old) and women (n = 17, age: 22.5 ± 3.4 years old) separately. For all BIA devices, there were no differences in the %FM values between the control and the other conditions in men or women (- 1.9 to 0.4%, p > 0.05). Across the three devices and five conditions, 97% of %FM tests returned values within 5% of control (2 tests), and 86% of tests were within 2% of control despite violating an assumption. The errors were greatest with dehydration and women were more likely to have a %FM difference greater than 2% than men with dehydration using the hand-to-foot device (Tanita TBF-314: 59% versus 9%). There were no differences in %FM between control and the conditions when examined by BMI (overweight/obesity: - 2.8 to 0.1% and normal weight: - 1.7 to 0.5%; BMI*trial, p = 0.99). %FM estimates were similar despite acutely violating the preliminary measurement BIA assumptions across a range of different BMIs. The minor variations in %FM are smaller than what would be expected with day-to-day variability or weight loss intervention but may be larger in women than men.