1,721,259 research outputs found
Individual differences in apparent energy digestibility are larger than generally recognized
No full textDisturbances in energy balance are responsible for 2 of the world's major health problems: obesity and protein-calorie malnutrition. Even small positive or negative excursions in energy balance lead to relatively large changes in body weight over prolonged time period
Are adult body circumferences associated with height? Relevance to normative ranges and circumferential indexes.
No full textBACKGROUND: Weight scales as height squared, which is an observation that forms the basis of body mass index (weight/height(2)). If, and how, circumferences, including waist circumference (WC) and hip circumference (HC), scale to height remains unclear, but this is an important consideration when developing normative ranges or applying WC/height and HC/height as risk indexes.OBJECTIVE: The study aim was to examine the scaling of weight, WC, and HC to height in NHANES (National Health and Nutrition Examination Survey) III participants.DESIGN: Subjects were adult non-Hispanic white, non-Hispanic black, and Mexican American men (n = 7422) and nonpregnant women (n = 7999) who had complete demographic and anthropometric data. In addition to height, allometric models were developed for each measure that controlled for age, race, and self-reported health status.RESULTS: After adjustment for age and race, weight scaled to height in men and women with mean (±SEE) powers of 2.29 ± 0.11 and 1.80 ± 0.07, respectively (both P < 0.001). Although univariate circumference-height models were weak or nonsignificant, when adjusted for age and race WC and HC scaled to height with powers of 0.76 ± 0.08 and 0.45 ± 0.05, respectively, in men and 0.80 ± 0.05 and 0.53 ± 0.04, respectively, in women (all P < 0.001). Age- and race-adjusted incremental increases in circumferences ranged from 0.2 to 0.5 cm per centimeter increase in height. Both WC/height and HC/height scaled negatively to height in men and women, and WC/HC scaled negatively to height in women only (all P < 0.001). Health status-adjusted models were similar.CONCLUSIONS: Circumferences and related ratios scale significantly to height, notably after adjustment for age and race, across subjects who are representative of the US population. These observations have implications for the clinical and epidemiologic use of these anthropometric measures and indexes
Percentage of body fat cutoffs by sex, age, and race-ethnicity in the US adult population from NHANES 1999-2004
No full textTo date, there is no consensus regarding adult cutoffs of percentage of body fat or estimated cutoffs on the basis of nationally representative samples with rigorous body-composition measurements.Background: To date, there is no consensus regarding adult cutoffs of percentage of body fat or estimated cutoffs on the basis of nationally representative samples with rigorous body-composition measurements. Objective: We developed cutoffs of percentage of body fat on the basis of the relation between dual-energy x-ray absorptiometry-measured fat mass and BMI (in kg/m(2)) stratified by sex, age, and race-ethnicity by using 1999-2004 NHANES data. Design: A simple regression (percentage of body fat = beta(0) + beta(1) x 1 divided by BMI) was fit for each combination of sex (men and women), 3 age groups (18-29, 30-49, and 50-84 y of age), and 3 race-ethnicity groups (non-Hispanic whites, non-Hispanic blacks, and Mexican Americans). Model fitting included a consideration of complex survey design and multiple imputations. Cutoffs of percentage of body fat were computed that corresponded to BMI cutoffs of 18.5, 25, 30, 35, and 40 on the basis of estimated prediction equations. Results: R-2 ranged from 0.54 to 0.72 for men (n = 6544) and 0.58 to 0.79 for women (n = 6362). In men, the percentage of body fat that corresponded to a BMI of 18.5, 25, 30, 35, and 40 across age and racial-ethnic groups ranged from 12.2% to 19.0%, 22.6% to 28.0%, 27.5% to 32.3%, 31.0% to 35.3%, and 33.6% to 37.6%, respectively; the corresponding ranges in women were from 24.6% to 32.3%, 35.0% to 40.2%, 39.9% to 44.1%, 43.4% to 47.1%, and 46.1% to 49.4%, respectively. The oldest age group had the highest cutoffs of percentage of body fat. Non-Hispanic blacks had the lowest cutoffs of percentage of body fat. Cutoffs of percentage of body fat were higher in women than in men. Conclusions: Cutoffs of percentage of body fat that correspond to the current US BMI cutoffs are a function of sex, age, and race-ethnicity. These factors should be taken into account when considering the appropriateness of levels of percentage of body fat
Association of lean tissue and fat mass with bone mineral content in children and adolescents
No full textThere has been uncertainty in the adult body composition literature about whether fat mass (FM) or fat free mass is a better predictor of bone mineral content and bone mineral density. This issue has recently also been raised in the pediatric literature. Based on suggested skeletal muscle-bone relationships, this study tested the hypothesis that in children and adolescents lean tissue mass (LTM) is a better predictor of total bone mineral content (TBMC) than is FM
Sarcopenia in Ageing and Chronic Illness: Trial Endpoints and Regulatory Issues
No full textABSTRACT In December 2024, the Society on Cachexia and Wasting Disorders (SCWD) hosted a Regulatory and Trial Update Workshop in Washington, D.C., bringing together experts from academia, industry, and the US Food and Drug Administration (FDA). This article summarizes key topics discussed during the meeting, including diagnostic challenges, emerging assessment methods, and trial endpoints. The D 3 ‐creatine dilution technique was highlighted as a promising tool for evaluating muscle mass. Additionally, the workshop addressed variability in computed tomography‐based lumbar skeletal muscle index measurements, emphasizing sources of variation at the instrument, imaging, and reader levels, as well as biological and clinical fluctuations. Discussions also focused on clinical trial endpoints for sarcopenia, particularly validated physical performance measures such as the Short Physical Performance Battery (SPPB), habitual gait speed, stair‐climb tests, and the 6‐min walk test. Furthermore, novel therapeutic approaches were explored, including 20‐hydroxyecdysone, enobosarm, anamorelin, ponsegromab, and nutritional supplementation, alongside broader strategies targeting myostatin‐activin signalling inhibition and Akt pathway activation. During the meeting, it was made clear that from a regulatory treatment development standpoint, clinically meaningful changes in patient‐reported outcomes, physical function and/or morbidity/mortality need to be shown. If the latter is not an efficacy endpoint, safety needs to be documented. Given that the population that may be addressed in aging associated sarcopenia is vast, the safety requirement standards applied for studies may be equivalent to those of studies in type 2 diabetes mellitus. Some argued at the meeting that this would make study programs so large that from an economic standpoint only therapies that significantly impact on morbidity/mortality outcomes have a chance to be considered commercially feasible for development
Identifying Athlete Body-Fluid Changes During a Competitive Season With Bioelectrical Impedance Vector Analysis
Full text linkPurpose: To analyze the association between body fluid changes evaluated by bioelectrical impedance vector analysis and dilution techniques over a competitive season in athletes. Methods: A total of 58 athletes of both sexes (men: age 18.7 [4.0] y and women: age 19.2 [6.0] y) engaging in different sports were evaluated at the beginning (pre) and 6 months after (post) the competitive season. Deuterium dilution and bromide dilution were used as the criterion methods to assess total body water (TBW) and extracellular water (ECW), respectively; intracellular water (ICW) was calculated as TBW–ECW. Bioelectrical resistance and reactance were obtained with a phase-sensitive 50-kHz bioelectrical impedance analysis device; bioelectrical impedance vector analysis was applied. Dual-energy X-ray absorptiometry was used to assess fat mass and fat-free mass. The athletes were empirically classified considering TBW change (pre–post, increase or decrease) according to sex. Results: Significant mean vector displacements in the postgroups were observed in both sexes. Specifically, reductions in vector length (Z/H) were associated with increases in TBW and ICW (r = −.718, P < .01; r = −.630, P < .01, respectively) and decreases in ECW:ICW ratio (r = .344, P < .05), even after adjusting for age, height, and sex. Phase-angle variations were positively associated with TBW and ICW (r = .458, P < .01; r = .564, P < .01, respectively) and negatively associated with ECW:ICW (r = −.436, P < .01). Phase angle significantly increased in all the postgroups except in women in whom TBW decreased. Conclusions: The results suggest that bioelectrical impedance vector analysis is a suitable method to obtain a qualitative indication of body fluid changes during a competitive season in athletes
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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