Association between bioelectrical impedance analysis parameters and muscle-related measurements obtained using a non-diagnostic ultrasound-based technique

Background: An in-depth analysis of body composition (BC) is fundamental for the assessment of nutritional status. A multifactorial approach is important for this assessment, integrating parameters and measurements obtained through different techniques, most notably bioelectrical impedance analysis (BIA) and ultrasound. In this study, we aimed to evaluate associations between BIA parameters and ultrasound measurements. Methods: The BC of 993 adults (539 women and 454 men) was evaluated using BIA (BIA 101 RJL, Akern Bioresearch, Florence, Italy) and a non-diagnostic ultrasound-based technique at the thigh, employing a 2.5 MHz, A-mode probe (BodyMetrixTM, IntelaMetrix, Inc., Livermore, CA, USA). Ultrasound scans were analysed using Adipometria v 1.8.8 software (Hosand Technologies s.r.l., Verbania, Italy) and the muscle echogenicity (EG) was obtained. Ultrasound measurements were correlated with BIA parameters. Results: In the total population, muscle EG was directly correlated with the BIA parameter resistance (r = 0.347) and inversely correlated with several BIA parameters, including intracellular water (r = -0.479 and - 0.386, % and L, respectively) and phase angle (r = -0.487). These associations were maintained even after stratification of subjects by sex. Conclusion: The observation of significant associations between BIA parameters and ultrasound measurements suggests the importance of not considering the two methods as exclusive, but of integrating them into a holistic approach for the in-depth assessment of BC and nutritional status. Such an approach provides detailed information for the identification of optimal nutritional treatment, its monitoring over time, and possible optimisation.