Prediction of percent body fat measurements in Americans 8 years and older

Although numerous equations to predict percent body fat have been published, few have broad generalizability. The objective of this study was to develop sets of equations that are generalizable to the American population 8 years of age and older

Advanced body composition assessment: from body mass index to body composition profiling

This paper gives a brief overview of common non-invasive techniques for body composition analysis and a more in-depth review of a body composition assessment method based on fatreferenced quantitative MRI. Earlier published studies of this method are summarized, and a previously unpublished validation study, based on 4753 subjects from the UK Biobank imaging cohort, comparing the quantitative MRI method with dualenergy X-ray absorptiometry (DXA) is presented. For whole-body measurements of adipose tissue (AT) or fat and lean tissue (LT), DXA and quantitative MRIs show excellent agreement with linear correlation of 0.99 and 0.97, and coefficient of variation (CV) of 4.5 and 4.6 per cent for fat (computed from AT) and LT, respectively, but the agreement was found significantly lower for visceral adipose tissue, with a CV of >20 per cent. The additional ability of MRI to also measure muscle volumes, muscle AT infiltration and ectopic fat, in combination with rapid scanning protocols and efficient image analysis tools, makes quantitative MRI a powerful tool for advanced body composition assessment

Nationally representative equations that include resistance and reactance for the prediction of percent body fat in Americans

Resistance and reactance collected by bioelectrical impedance (BIA) can be used in equations to estimate percent body fat at relatively low cost and subject burden. To our knowledge no such equations have been developed in a nationally representative sample

The end of body composition methodology research?

PURPOSE OF REVIEW: Over one century of research has led to methods for measuring all major body components at the atomic, molecular, cellular, and tissue-system levels. These remarkable developments have fueled a rapid and sustained increase in 'body composition' biological findings and related publications. Other than small, incremental improvements in available methods, is there no longer a need for developing new body composition methods? This review examines the question: are we approaching the 'end' of body composition methodology research? RECENT FINDINGS: Emerging and rapidly growing areas outside of 'traditional' body composition research are highlighting the need for new and innovative method development. Recently introduced technologies such as positron emission tomography and functional magnetic resonance imaging extend 'mass' estimates to corresponding 'function' and physiology in humans. Although all major components are now measurable in humans, large gaps remain when considering factors such as radiation exposure, invasiveness, static versus dynamic measurements, and laboratory versus clinic and field assessments. SUMMARY: The end of the first phase of body composition method development has now arrived: all major components are measurable in vivo. The accessibility of these methods is stimulating rapid advances in biological knowledge surrounding human body composition from in utero to old age. Sustaining advances in new body composition method development will require extending the boundaries of the field as it now exists

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 < 0.01; males: \u3b2 = 2.70, p < 0.01) and E:I (males and females: \u3b2 = 120.08; p < 0.01); R explained TBW (females: \u3b2 = 120.03; p < 0.01; males: \u3b2 = 120.06; p < 0.01) and ECW (females: \u3b2 = \u20130.02, p < 0.01; males: \u3b2 = 120.03, p < 0.01) and ICW (females: \u3b2 = \u20130.01, p < 0.053; males: \u3b2 = \u20130.03 p < 0.01); and Xc predicted ECW (females: \u3b2 = 120.06, p < 0.01; males: \u3b2 = 120.12, p < 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

Childhood obesity intervention studies: A narrative review and guide for investigators, authors, editors, reviewers, journalists, and readers to guard against exaggerated effectiveness claims

Being able to draw accurate conclusions from childhood obesity trials is important to make advances in reversing the obesity epidemic. However, obesity research sometimes is not conducted or reported to appropriate scientific standards. To constructively draw attention to this issue, we present 10 errors that are commonly committed, illustrate each error with examples from the childhood obesity literature, and follow with suggestions on how to avoid these errors. These errors are as follows: using self-reported outcomes and teaching to the test; foregoing control groups and risking regression to the mean creating differences over time; changing the goal posts; ignoring clustering in studies that randomize groups of children; following the forking paths, subsetting, p-hacking, and data dredging; basing conclusions on tests for significant differences from baseline; equating “no statistically significant difference” with “equally effective”; ignoring intervention study results in favor of observational analyses; using one-sided testing for statistical significance; and stating that effects are clinically significant even though they are not statistically significant. We hope that compiling these errors in one article will serve as the beginning of a checklist to support fidelity in conducting, analyzing, and reporting childhood obesity research

Towards a definition of sarcopenia--results from epidemiologic studies

The age-related loss of muscle mass, also called sarcopenia, is receiving increasing attention in aging research. While the concept is frequently being used in research settings and introduced to clinical settings, thus far no consensus on its definition has been established. This article provides an overview of the history of sarcopenia definitions proposed in the literature thus far. It will describe the methodology used to develop the cutpoints for low muscle mass (or strength) in large epidemiological studies, how sarcopenia based on these cutpoints relates to functional outcomes, and the advantages and disadvantages of the different definitions. This overview will contribute to the current need to develop a consensus definition of sarcopenia which can be used in all relevant settings. The Journal of Nutrition, Health & Aging©