Phase Angle and Impedance Ratio: Reference Cut-Points From the United States National Health and Nutrition Examination Survey 1999-2004 From Bioimpedance Spectroscopy Data.

Background: Raw bioimpedance parameters (eg, 50-kHz phase angle [PA] and 200-kHz/5-kHz impedance ratio [IR]) have been investigated as predictors of nutrition status and/or clinical outcomes. However, their validity as prognostic measures depends on the availability of appropriate reference data. Using a large and ethnically diverse data set, we aimed to determine if ethnicity influences these measures and provide expanded bioimpedance reference data for the U.

Relationship between body fat and BMI in a US hispanic population-based cohort study: Results from HCHS/SOL.

Objective: To evaluate the percentage of body fat (%BF)-BMI relationship, identify %BF levels corresponding to adult BMI cut points, and examine %BF-BMI agreement in a diverse Hispanic/Latino population.

Methods: %BF by bioelectrical impedance analysis was corrected against %BF by (18) O dilution in 434 participants of the ancillary Hispanic Community Health Study/Study of Latinos. Corrected %BF was regressed against 1/BMI in the parent study (n = 15,261), fitting models for each age group, by sex, and Hispanic/Latino background; predicted %BF was then computed for each BMI cut point.

Measuring body composition in low-resource settings across the life course.

We explore recent advances in the field of body composition measurement that could be suitable for use in low-resource settings across the life-course. Our aim was three-fold: (i) to review the available literature and information on both current and novel technologies for body composition measurement, (ii) to present a decision schema that may assist in selecting the appropriate body composition technology, and (iii) which of the technologies available are suitable for low-resource settings based on cost, infrastructure needed, participant compliance needed for the measurement, quality assurance protocols in place, safety, accuracy of measurement and training required.

Universal equation for estimating ideal body weight and body weight at any BMI.

Background: Ideal body weight (IBW) equations and body mass index (BMI) ranges have both been used to delineate healthy or normal weight ranges, although these 2 different approaches are at odds with each other. In particular, past IBW equations are misaligned with BMI values, and unlike BMI, the equations have failed to recognize that there is a range of ideal or target body weights.

Objective: For the first time, to our knowledge, we merged the concepts of a linear IBW equation and of defining target body weights in terms of BMI.

Exercise: Is More Always Better?

Do greater levels of exercise always promote relatively higher levels of daily energy expenditure and health? Recent studies challenge the traditional assumption that 'more exercise is better' by suggesting daily energy expenditure and health plateaus are reached beyond which incremental gains are minimal.

Change in Obesity Prevalence across the United States Is Influenced by Recreational and Healthcare Contexts, Food Environments, and Hispanic Populations.

Objective: To examine change in county-level adult obesity prevalence between 2004 and 2009 and identify associated community characteristics.

Methods: Change in county-level adult (≥20 years) obesity prevalence was calculated for a 5-year period (2004-2009). Community measures of economic, healthcare, recreational, food environment, population structure, and education contexts were also calculated.

Phase angle and its determinants in healthy subjects: influence of body composition.

Background: The phase angle (PA) has been used as a prognostic marker in several clinical situations. Nevertheless, its biological meaning is not completely understood.

Objective: We verified how body-composition components could explain the PA.

New compartment model analysis of lean-mass and fat-mass growth with overfeeding.

Objectives: Mathematical models of lean- and fat-mass growth with diet are useful to help describe and potentially predict the fat- and lean-mass change with different diets as a function of consumed protein and fat calories. Most of the existing models do not explicitly account for interdependence of fat-mass on the lean-mass and vice versa. The aim of this study was to develop a new compartmental model to describe the growth of lean and fat mass depending on the input of dietary protein and fat, and accounting for the interdependence of adipose tissue and muscle growth.

Mobile evaluation of human energy balance and weight control: Potential for future developments.

Quantification of energy storage is essential in understanding energy balance and can be determined by bioelectrical impedance analysis (BIA). Here, we have developed a smartphone form factor multi-frequency BIA device that incorporates an analog front end for body composition measurements. The device was compared against a reference gel-electrode based BIA system in a clinical trial of 311 subjects for predicting BIA equations by calibrating the impedance index to body composition data from dual energy X-ray absorptiometry (DXA).

Body adiposity index performance in estimating body fat in a sample of severely obese Brazilian patients.

Background/objectives: The body adiposity index (BAI) estimates the amount of body fat (BF) in humans. In Mexican-American and African-American populations, BAI has performed better than body mass index (BMI). The aim of this study was to evaluate the performance of BAI in estimating percentage (BF%) in severely obese Brazilian patients, with air displacement plethysmography (ADP) used as the reference method.

Dudrick Research Symposium 2015-Lean Tissue and Protein in Health and Disease.

The 2015 Dudrick Research Symposium "Lean Tissue and Protein in Health and Disease: Key Targets and Assessment Strategies" was held on February 16, 2015, at Clinical Nutrition Week in Long Beach, California. The Dudrick Symposium honors the many pivotal and innovative contributions to the development and advancement of parenteral nutrition made by Dr Stanley J. Dudrick, physician scientist, academic leader, and a founding member of the American Society for Parenteral and Enteral Nutrition.

Emerging Technologies and their Applications in Lipid Compartment Measurement.

Non-Communicable diseases (NCDs), including obesity, are emerging as the major health concern of the 21st century. Excess adiposity and related NCD metabolic disturbances have stimulated development of new lipid compartment measurement technologies to help us to understand cellular energy exchange, to refine phenotypes, and to develop predictive markers of adverse clinical outcomes. Recent advances now allow quantification of multiple intracellular lipid and adipose tissue compartments that can be evaluated across the human lifespan.

Derivation and validation of simple anthropometric equations to predict adipose tissue mass and total fat mass with MRI as the reference method.

The reference organ-level body composition measurement method is MRI. Practical estimations of total adipose tissue mass (TATM), total adipose tissue fat mass (TATFM) and total body fat are valuable for epidemiology, but validated prediction equations based on MRI are not currently available. We aimed to derive and validate new anthropometric equations to estimate MRI-measured TATM/TATFM/total body fat and compare them with existing prediction equations using older methods.

Smartphone-Based Bioelectrical Impedance Analysis Devices for Daily Obesity Management.

Current bioelectric impedance analysis (BIA) systems are often large, cumbersome devices which require strict electrode placement on the user, thus inhibiting mobile capabilities. In this work, we developed a handheld BIA device that measures impedance from multiple frequencies (5 kHz~200 kHz) with four contact electrodes and evaluated the BIA device against standard body composition analysis systems: a dual-energy X-ray absorptiometry (DXA) system (GE Lunar Prodigy, GE Healthcare, Buckinghamshire, UK) and a whole-body BIA system (InBody S10, InBody, Co. Ltd, Seoul, Korea).

Body composition phenotypes and obesity paradox.

Purpose Of Review: The obesity paradox is a highly controversial concept that may be attributed to methodological limitations related to its identification. One of the primary concerns is the use of BMI to define obesity. This index does not differentiate lean versus adipose tissue compartments (i.

Quantitative Comparison of 2 Dual-Energy X-ray Absorptiometry Systems in Assessing Body Composition and Bone Mineral Measurements.

Dual-energy X-ray absorptiometry (DXA) is widely used in body composition measurement and evaluation. Because of its numerous applications, the probability of instrument discrepancies has increased dramatically. This study quantitatively compares 2 different DXA systems.

The Pattern of Gestational Weight Gain is Associated with Changes in Maternal Body Composition and Neonatal Size.

Objectives: The pattern of gestational weight gain (GWG) reflects general nutrient availability to support growing fetal and maternal compartments and may contribute to later health, but how it relates to changes in maternal body composition is unknown. We evaluated how the pattern of GWG related to changes in maternal body composition during pregnancy and infant size at birth.

Methods: A prospective, multi-ethnic cohort of 156 pregnant women and their infants was studied in New York City.

Effect of parallel radiofrequency transmission on arterial input function selection in dynamic contrast-enhanced 3 Tesla pelvic MRI.

Background: To evaluate whether parallel radiofrequency transmission (mTX) can improve the symmetry of the left and right femoral arteries in dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) of prostate and bladder cancer.

Methods: Eighteen prostate and 24 bladder cancer patients underwent 3.0 Tesla DCE-MRI scan with a single transmission channel coil.

Ignoring regression to the mean leads to unsupported conclusion about obesity.

Childhood obesity remains a substantial health concern for our population and thoughtful attempts to develop and evaluate the utility of programs to reduce childhood obesity levels are needed. Unfortunately, we believe the conclusion by Burke et al. that the HealthMPowers program produces positive change in body composition is incorrect because the results obtained are likely due to regression to the mean (RTM), a well-known threat to the validity of studies that is often overlooked.

Skeletal muscle mass and quality: evolution of modern measurement concepts in the context of sarcopenia.

The first reports of accurate skeletal muscle mass measurement in human subjects appeared at about the same time as introduction of the sarcopenia concept in the late 1980s. Since then these methods, computed tomography and MRI, have been used to gain insights into older (i.e.