A tribute to Antonio Piccoli, a father and a pioneer in body composition assessment using bioelectrical impedance technology

Postprint (author's final draft

Phase angle in localized bioimpedance measurements to assess and monitor muscle injury

Localized bioimpedance (L-BIA) measurements are an innovative method to non-invasively identify structural derangement of soft tissues, principally muscles, and fluid accumulation in response to traumatic injury. This review provides unique L-BIA data demonstrating significant relative differences between injured and contralateral non-injured regions of interest (ROI) associated with soft tissue injury. One key finding is the specific and sensitive role of reactance (Xc), measured at 50 kHz with a phase-sensitive BI instrument, to identify objective degrees of muscle injury, localized structural damage and fluid accretion, determined using magnetic resonance imaging. The predominant effect of Xc as an indicator of severity of muscle injury is highlighted in phase angle (PhA) measurements. Novel experimental models utilizing cooking-induced cell disruption, saline injection into meat specimens, and measurements of changing amounts of cells in a constant volume provide empirical evidence of the physiological correlates of series Xc as cells in water. Findings of strong associations of capacitance, computed from parallel Xc (XCP), with whole body counting of 40-potassium and resting metabolic rate support the hypothesis that parallel Xc is a biomarker of body cell mass. These observations provide a theoretical and practical basis for a significant role of Xc, and hence PhA, to identify objectively graded muscle injury and to reliably monitor progress of treatment and return of muscle function.Peer ReviewedPostprint (author's final draft

Digital single-image smartphone assessment of total body fat and abdominal fat using machine learning

Background: Obesity is chronic health problem. Screening for the obesity phenotype is limited by the availability of practical methods. Methods: We determined the reproducibility and accuracy of an automated machine-learning method using smartphone camera-enabled capture and analysis of single, two-dimensional (2D) standing lateral digital images to estimate fat mass (FM) compared to dual X-ray absorptiometry (DXA) in females and males. We also report the first model to predict abdominal FM using 2D digital images. Results: Gender-specific 2D estimates of FM were significantly correlated (p 0.05). Reproducibility of FM estimates was very high (R2 = 0.99) with high concordance (R2 = 0.99) and low absolute pure error (0.114 to 0.116 kg) and percent error (1.3 and 3%). Bland–Altman plots revealed no proportional bias with limits of agreement of 4.9 to -4.3 kg and 3.9 to -4.9 kg for females and males, respectively. A novel 2D model to estimate abdominal (lumbar 2–5) FM produced high correlations (R2 = 0.99) and concordance (R2 = 0.99) compared to DXA abdominal FM values. Conclusions: A smartphone camera trained with machine learning and automated processing of 2D lateral standing digital images is an objective and valid method to estimate FM and, with proof of concept, to determine abdominal FM. It can facilitate practical identification of the obesity phenotype in adults.Peer ReviewedPostprint (published version

Food Security, Depression and Quality of Life in Northern Plains Indians

Major health disparities, high levels of poverty and food insecurity exist in many Native American and Alaskan Native (AI/AN) communities. Relatively little research has been done on these issues and possible relationships between them. A research program was designed with the objective of exploring the relationships between these various issues, if any existed, in one sub-group of AI/AN. In the study, the incidence of food insecurity was determined in a convenience sample of Northern Plains Indians (NPI) and correlated with measures of physical and mental health, body composition, quality of life, cultural identification and dietary intakes. Participants were 458 adult attendees at summer powwows and health fairs held at 5 reservations and 3 tribal colleges in North Dakota and western Minnesota. Participants completed various measurements and assessments and pertinent health and demographic data were recorded. Observed incidences of “food insecurity” overall and “very low food security” in particular (26.4% and 10.4%, respectively) were in sharp contrast to recently reported rates for North Dakota (8.7% and 3.4%) and the U.S. population as a whole (14.7% and 5.6%). In this manuscript, analysis revealed a positive relationship between food insecurity and depression and a negative relationship between food insecurity and quality of life. The findings emphasize the need to address food insecurity when designing research and service programs to address depression in AI/AN populations

Fluid-dependent single-frequency bioelectrical impedance fat mass estimates compared to digital imaging and dual X-ray absorptiometry

The need for a practical method for routine determination of body fat has progressed from body mass index (BMI) to bioelectrical impedance analysis (BIA) and smartphone two-dimensional imaging. We determined agreement in fat mass (FM) estimated with 50 kHz BIA and smartphone single lateral standing digital image (SLSDI) compared to dual X-ray absorptiometry (DXA) in 188 healthy adults (69 females and 119 males). BIA underestimated (p 25 kg/m2, 54 male rugby players, compared to 40 male non-rugby players, had greater (p < 0.001) BMI and FFM but less (p < 0.001) FM and ECW/ICW. BIA underestimated (p < 0.001) FM in the non-rugby men, but SLSDI and DXA FM estimates were not different in both groups. This finding is consistent with the expansion of ECW in individuals with excess body fat due to increased adipose tissue mass and its water content. Unlike SLSDI, 50 kHz BIA predictions of FM are affected by an increased ECW/ICW associated with greater adipose tissue. These findings demonstrate the validity, practicality, and convenience of smartphone SLSDI to estimate FM, seemingly not influenced by variable hydration states, for healthcare providers in clinical and field settings.Peer ReviewedPostprint (published version

Return-to-play according to GAP in muscle injuries by L-BIA measurements: clinical prognosis.

Postprint (author's final draft

Detection of muscle gap by L-BIA in muscle injuries: clinical prognosis

Sport-related muscle injury classifications are based basically on imaging criteria such as ultrasound (US) and magnetic resonance imaging (MRI) without consensus because of a lack of clinical prognostics for return-to-play (RTP), which is conditioned upon the severity of the injury, and this in turn with the muscle gap (muscular fibers retraction). Recently, Futbol Club Barcelona's medical department proposed a new muscle injury classification in which muscle gap plays an important role, with the drawback that it is not always possible to identify by MRI. Localized bioimpedance measurement (L-BIA) has emerged as a non-invasive technique for supporting US and MRI to quantify the disrupted soft tissue structure in injured muscles. Objective: To correlate the severity of the injury according to the gap with the RTP, through the percent of change in resistance (R), reactance (Xc) and phase-angle (PA) by L-BIA measurements in 22 muscle injuries. Main results: After grouping the data according to the muscle gap (by MRI exam), there were significant differences in R between grade 1 and grade 2f (myotendinous or myofascial muscle injury with feather-like appearance), as well as between grade 2f and grade 2g (myotendinous or myofascial muscle injury with feather and gap). The Xc and PA values decrease significantly between each grade (i.e. 1 versus 2f, 1 versus 2g and 2f versus 2g). In addition, the severity of the muscle gap adversely affected the RTP with significant differences observed between 1 and 2g as well as between 2f and 2g. Significance: These results show that L-BIA could aid MRI and US in identifying the severity of an injured muscle according to muscle gap and therefore to accurately predict the RTP.Peer ReviewedPostprint (published version

The predictive role of raw bioelectrical impedance parameters in water compartments and fluid distribution assessed by dilution techniques in athletes

The aims of this study were to analyze the usefulness of raw bioelectrical impedance (BI) parameters in assessing water compartments and fluid distribution in athletes. A total of 202 men and 71 female athletes were analyzed. Total body water (TBW) and extracellular water (ECW) were determined by dilution techniques, while intracellular water (ICW) was calculated. Fluid distribution was calculated as the ECW/ICW ratio (E:I). Phase angle (PhA), resistance (R) and reactance (Xc) were obtained through BI spectroscopy using frequency 50kHz. Fat (FM) and fat\u2010free mass (FFM) were assessed by dual\u2010energy X\u2010ray absorptiometry. After adjusting for height, FM, FFM, age and sports category we observed that: PhA predicted ICW (females: \u3b2 = 1.62, p &lt; 0.01; males: \u3b2 = 2.70, p &lt; 0.01) and E:I (males and females: \u3b2 = 120.08; p &lt; 0.01); R explained TBW (females: \u3b2 = 120.03; p &lt; 0.01; males: \u3b2 = 120.06; p &lt; 0.01) and ECW (females: \u3b2 = \u20130.02, p &lt; 0.01; males: \u3b2 = 120.03, p &lt; 0.01) and ICW (females: \u3b2 = \u20130.01, p &lt; 0.053; males: \u3b2 = \u20130.03 p &lt; 0.01); and Xc predicted ECW (females: \u3b2 = 120.06, p &lt; 0.01; males: \u3b2 = 120.12, p &lt; 0.01). A higher PhA is a good predictor of a larger ICW pool and a lower E:I, regardless of body composition, age, height, and sports category. Lower R is associated with higher water pools whereas ECW expansion is explained by lower Xc. Raw BI parameters are useful predictors of total and extracellular pools, cellular hydration and fluid distribution in athletes