JoVE Visualize What is visualize?
Stop Reading. Start Watching.
Advanced Search
Stop Reading. Start Watching.
Regular Search
Find video protocols related to scientific articles indexed in Pubmed.
Body Mass Index and the Risk of All-Cause Mortality Among Patients with Type 2 Diabetes.
Circulation
PUBLISHED: 11-08-2014
Show Abstract
Hide Abstract
-Several prospective studies have evaluated the association between body mass index (BMI) and death risk among patients with diabetes; however, the results have been inconsistent.
Related JoVE Video
Lean tissue imaging: a new era for nutritional assessment and intervention.
JPEN J Parenter Enteral Nutr
PUBLISHED: 09-19-2014
Show Abstract
Hide Abstract
Body composition refers to the amount of fat and lean tissues in our body; it is a science that looks beyond a unit of body weight, accounting for the proportion of different tissues and its relationship to health. Although body weight and body mass index are well-known indexes of health status, most researchers agree that they are rather inaccurate measures, especially for elderly individuals and those patients with specific clinical conditions. The emerging use of imaging techniques such as dual energy x-ray absorptiometry, computerized tomography, magnetic resonance imaging, and ultrasound imaging in the clinical setting have highlighted the importance of lean soft tissue (LST) as an independent predictor of morbidity and mortality. It is clear from emerging studies that body composition health will be vital in treatment decisions, prognostic outcomes, and quality of life in several nonclinical and clinical states. This review explores the methodologies and the emerging value of imaging techniques in the assessment of body composition, focusing on the value of LST to predict nutrition status.
Related JoVE Video
Body composition indices of a load-capacity model: gender- and BMI-specific reference curves.
Public Health Nutr
PUBLISHED: 09-16-2014
Show Abstract
Hide Abstract
Fat mass (FM) and fat-free mass (FFM) are frequently measured to define body composition phenotypes. The load-capacity model integrates the effects of both FM and FFM to improve disease-risk prediction. We aimed to derive age-, gender- and BMI-specific reference curves of load-capacity model indices in an adult population (?18 years).
Related JoVE Video
Derivation and validation of simple equations to predict total muscle mass from simple anthropometric and demographic data.
Am. J. Clin. Nutr.
PUBLISHED: 08-13-2014
Show Abstract
Hide Abstract
Muscle mass reflects and influences health status. Its reliable estimation would be of value for epidemiology.
Related JoVE Video
Effect of dietary adherence on the body weight plateau: a mathematical model incorporating intermittent compliance with energy intake prescription.
Am. J. Clin. Nutr.
PUBLISHED: 07-30-2014
Show Abstract
Hide Abstract
Clinical weight loss in individuals typically stabilizes at 6 mo. However, validated models of dynamic energy balance have consistently shown weight plateaus between 1 and 2 y. The cause for this discrepancy is unclear.
Related JoVE Video
Scaling of adult regional body mass and body composition as a whole to height: Relevance to body shape and body mass index.
Am. J. Hum. Biol.
PUBLISHED: 07-29-2014
Show Abstract
Hide Abstract
Adult body mass (MB) empirically scales as height (Ht) squared (MB ? Ht(2) ), but does regional body mass and body composition as a whole also scale as Ht(2) ? This question is relevant to a wide range of biological topics, including interpretation of body mass index (BMI).
Related JoVE Video
Weighing the Evidence of Common Beliefs in Obesity Research.
Crit Rev Food Sci Nutr
PUBLISHED: 06-21-2014
Show Abstract
Hide Abstract
Abstract Obesity is a topic on which many views are strongly held in the absence of scientific evidence to support those views, and some views are strongly held despite evidence to contradict those views. We refer to the former as "presumptions" and the latter as "myths". Here we present nine myths and ten presumptions surrounding the effects of rapid weight loss; setting realistic goals in weight loss therapy; stage of change or readiness to lose weight; physical education classes; breast-feeding; daily self-weighing; genetic contribution to obesity; the "Freshman 15"; food deserts; regularly eating (versus skipping) breakfast; eating close to bedtime; eating more fruits and vegetables; weight cycling (i.e. yo-yo dieting); snacking; built environment; reducing screen time in childhood obesity; portion size; participation in family mealtime; and drinking water as a means of weight-loss. For each of these, we describe the belief and present evidence that the belief is widely held or stated, reasons to support the conjecture that the belief might be true, evidence to directly support or refute the belief, and findings from randomized controlled trials, if available. We conclude with a discussion of the implications of these determinations, conjecture on why so many myths and presumptions exist, and suggestions for limiting the spread of these and other unsubstantiated beliefs about obesity domain.
Related JoVE Video
A population-based approach to define body-composition phenotypes.
Am. J. Clin. Nutr.
PUBLISHED: 04-23-2014
Show Abstract
Hide Abstract
Abnormal body compositions such as high adiposity (HA), low muscle mass (LM), or a combination of the 2 [high adiposity with low muscle mass (HA-LM)] are relevant phenotypes, but data on their prevalence and impact on health are still limited. This is largely because of a lack of a consensus definition for these conditions. Of particular interest is the HA-LM phenotype, also termed "sarcopenic obesity," which may confer greater health risk.OBJECTIVE: We propose a new approach for operationalizing abnormal body-composition phenotypes in a representative adult population.DESIGN: Whole-body dual-energy X-ray absorptiometry data obtained from the 1999-2004 NHANES were analyzed for 13,236 subjects aged ?18 y (maximum weight and height of 136 kg and 1.96 m, respectively). Sex- and body mass index (BMI)-specific decile groups of appendicular skeletal muscle index (ASMI; kg/m(2)) and fat mass index (FMI; kg/m(2)) were developed. Cutoffs for HA and LM were incorporated into a diagnostic framework to characterize 4 specific body-composition phenotypes-low adiposity with high muscle mass, high adiposity with high muscle mass, low adiposity with low muscle mass, and HA-LM-and a subclassification of the phenotypes into classes I, II, and III.RESULTS: Abnormal phenotypes were prevalent across the age spectrum and BMI categories. The association between ASMI or FMI and age was modified by sex and BMI. The prevalence of HA-LM in the whole sample was 10.3% in women and 15.2% in men. The prevalence of all subclasses of HA-LM in obese women and men was 14.7% and 22.9%, respectively. HA-LM class III was more prevalent in obese men (2.3%) than in obese women (0.3%).CONCLUSIONS: We developed sex- and BMI-specific reference curves to harmonize the classification of body-composition phenotypes. The application of this classification will be particularly useful in the identification of cases of sarcopenic obesity. The association of these phenotypes with metabolic deregulation and increased disease risk awaits verification.
Related JoVE Video
Blood pressure and heart failure risk among diabetic patients.
Int. J. Cardiol.
PUBLISHED: 02-28-2014
Show Abstract
Hide Abstract
Blood pressure (BP) control has been shown to reduce the risk of heart failure (HF) among diabetic patients; however, it is not known whether the lowest clinical BP achieved ultimately results in the lowest risk of HF in diabetic patients.
Related JoVE Video
Hyperphagia: current concepts and future directions proceedings of the 2nd international conference on hyperphagia.
Obesity (Silver Spring)
PUBLISHED: 02-28-2014
Show Abstract
Hide Abstract
Hyperphagia is a central feature of inherited disorders (e.g., Prader-Willi Syndrome) in which obesity is a primary phenotypic component. Hyperphagia may also contribute to obesity as observed in the general population, thus raising the potential importance of common underlying mechanisms and treatments. Substantial gaps in understanding the molecular basis of inherited hyperphagia syndromes are present as are a lack of mechanistic of mechanistic targets that can serve as a basis for pharmacologic and behavioral treatments.
Related JoVE Video
Obesity paradox in cancer: new insights provided by body composition.
Am. J. Clin. Nutr.
PUBLISHED: 02-26-2014
Show Abstract
Hide Abstract
Obesity, defined by body mass index (BMI), appears to have a paradoxical protective effect in several chronic diseases.
Related JoVE Video
Effects of three intense sweeteners on fat storage in the C. elegans model.
Chem. Biol. Interact.
PUBLISHED: 01-15-2014
Show Abstract
Hide Abstract
Beverages sweetened with caloric sweeteners (CS), glucose, sucrose or high-fructose corn syrup, are associated with weight gain. Beverages sweetened with intense sweeteners (IS) are marketed as low-calorie substitutes to prevent beverages-associated weight gain. Using Caenorhabditis elegans, the effects on intestinal fat deposition (IFD) and pharyngeal pumping rate (PPR) of cola beverages sweetened with glucose, aspartame, or aspartame plus acesulfame-potassium (AceK) were compared. Control groups received Escherichia coli (OP50) only. Study I: the nematodes received additional glucose- or IS-sweetened beverages. Study II: the nematodes received additional glucose, aspartame, or aspartame plus AceK (AAK). Beverages containing CS or IS (aspartame or AAK) did not alter IFD in wild type (N2) or in daf-16 deficiency. The CS cola increased IFD in sir-2.1 deficiency (P<0.05). The AAK-cola increased IFD in daf-16/daf-2 deficiency and sir-2.1 deficiency (P<0.05). Glucose increased IFD in N2 and daf-16 deficiency (P<0.05). Aspartame showed a tendency towards reduced IFD in N2 and decreased IFD in daf-16/daf-2 deficiency (P<0.05). AAK increased IFD in daf-16 deficiency and sir-2.1 deficiency (P<0.05), and reversed the aspartame-induced reduction in IFD. The aspartame-sweetened cola increased the PPR in daf-16/daf-2 deficiency and daf-16 deficiency (P<0.05); similar results were obtained in N2 with both IS (P<0.05). AAK increased the PPR in daf-16/daf-2, daf-16, and sir-2.1 deficiencies (P<0.05). Thus, IS increased the PPR, a surrogate marker of lifespan. Aspartame may have an independent effect in reducing IFD to assist humans desiring weight loss. AceK may increase IFD in presence of insulin resistance.
Related JoVE Video
Assessing skeletal muscle mass: historical overview and state of the art.
J Cachexia Sarcopenia Muscle
PUBLISHED: 01-14-2014
Show Abstract
Hide Abstract
Even though skeletal muscle (SM) is the largest body compartment in most adults and a key phenotypic marker of sarcopenia and cachexia, SM mass was until recently difficult and often impractical to quantify in vivo. This review traces the historical development of SM mass measurement methods and their evolution to advances that now promise to provide in-depth noninvasive measures of SM composition.
Related JoVE Video
HbA1c and lower-extremity amputation risk in low-income patients with diabetes.
Diabetes Care
PUBLISHED: 09-23-2013
Show Abstract
Hide Abstract
Diabetes confers a very high risk of lower-extremity amputation (LEA); however, few studies have assessed whether blood glucose control can reduce LEA risk among patients with diabetes, especially in practice settings where low-income patients predominate.
Related JoVE Video
Advances in the understanding of specific metabolic rates of major organs and tissues in humans.
Curr Opin Clin Nutr Metab Care
PUBLISHED: 08-09-2013
Show Abstract
Hide Abstract
To present recent evidence on organ and tissue metabolic rates in humans to explain the variance in resting energy expenditure (REE).
Related JoVE Video
Anthropometric markers of obesity and mortality in white and African American adults: the pennington center longitudinal study.
Obesity (Silver Spring)
PUBLISHED: 06-21-2013
Show Abstract
Hide Abstract
The purpose of this study was to determine the association between anthropometric measures of obesity and all-cause mortality in white and African American men and women.
Related JoVE Video
Aggressive blood pressure control increases coronary heart disease risk among diabetic patients.
Diabetes Care
PUBLISHED: 05-20-2013
Show Abstract
Hide Abstract
Blood pressure control can reduce the risk of coronary heart disease (CHD) among diabetic patients; however, it is not known whether the lowest risk of CHD is among diabetic patients with the lowest blood pressure level.
Related JoVE Video
The paradox of overnutrition in aging and cognition.
Ann. N. Y. Acad. Sci.
PUBLISHED: 05-17-2013
Show Abstract
Hide Abstract
Populations of many countries are becoming increasingly overweight and obese, driven largely by excessive calorie intake and reduced physical activity; greater body mass is accompanied by epidemic levels of comorbid metabolic diseases. At the same time, individuals are living longer. The combination of aging and the increased prevalence of metabolic disease is associated with increases in aging-related comorbid diseases such as Alzheimers disease, cerebrovascular dementia, and sarcopenia. Here, correlative and causal links between diseases of overnutrition and diseases of aging and cognition are explored.
Related JoVE Video
Dynamic model predicting overweight, obesity, and extreme obesity prevalence trends.
Obesity (Silver Spring)
PUBLISHED: 04-01-2013
Show Abstract
Hide Abstract
Obesity prevalence in the United States appears to be leveling, but the reasons behind the plateau remain unknown. Mechanistic insights can be provided from a mathematical model. The objective of this study is to model known multiple population parameters associated with changes in body mass index (BMI) classes and to establish conditions under which obesity prevalence will plateau.
Related JoVE Video
Greater abdominal fat accumulation is associated with higher metabolic risk in Chinese than in white people: an ethnicity study.
PLoS ONE
PUBLISHED: 02-07-2013
Show Abstract
Hide Abstract
Chinese are reported to have a higher percent body fat (%BF) and a higher percent trunk fat (%TF) than whites for a given body mass index (BMI). However, the associations of these ethnic differences in body composition with metabolic risks remain unknown.
Related JoVE Video
Myths, presumptions, and facts about obesity.
N. Engl. J. Med.
PUBLISHED: 02-01-2013
Show Abstract
Hide Abstract
Many beliefs about obesity persist in the absence of supporting scientific evidence (presumptions); some persist despite contradicting evidence (myths). The promulgation of unsupported beliefs may yield poorly informed policy decisions, inaccurate clinical and public health recommendations, and an unproductive allocation of research resources and may divert attention away from useful, evidence-based information.
Related JoVE Video
Clinical utility and reproducibility of visceral adipose tissue measurements derived from dual-energy X-ray absorptiometry in white and african american adults.
Obesity (Silver Spring)
PUBLISHED: 01-31-2013
Show Abstract
Hide Abstract
The purpose of this study was to determine reproducibility and clinical thresholds for DXA-derived visceral adipose tissue (VAT).
Related JoVE Video
Clinical utility of visceral adipose tissue for the identification of cardiometabolic risk in white and African American adults.
Am. J. Clin. Nutr.
PUBLISHED: 01-30-2013
Show Abstract
Hide Abstract
Visceral adipose tissue (VAT) has been identified as a harmful fat depot, and sex and race differences in VAT have been reported in white and African Americans.
Related JoVE Video
Comparison of the Relationship Between Bone Marrow Adipose Tissue and Volumetric Bone Mineral Density in Children and Adults.
J Clin Densitom
PUBLISHED: 01-29-2013
Show Abstract
Hide Abstract
Several large-scale studies have reported the presence of an inverse relationship between bone mineral density (BMD) and bone marrow adipose tissue (BMAT) in adults. We aim to determine if there is an inverse relationship between pelvic volumetric BMD (vBMD) and pelvic BMAT in children and to compare this relationship in children and adults. Pelvic BMAT and bone volume (BV) was evaluated in 181 healthy children (5-17yr) and 495 healthy adults (?18yr) with whole-body magnetic resonance imaging (MRI). Pelvic vBMD was calculated using whole-body dual-energy X-ray absorptiometry to measure pelvic bone mineral content and MRI-measured BV. An inverse correlation was found between pelvic BMAT and pelvic vBMD in both children (r=-0.374, p<0.001) and adults (r=-0.650, p<0.001). In regression analysis with pelvic vBMD as the dependent variable and BMAT as the independent variable, being a child or adult neither significantly contribute to the pelvic BMD (p=0.995) nor did its interaction with pelvic BMAT (p=0.415). The inverse relationship observed between pelvic vBMD and pelvic BMAT in children extends previous findings that found the inverse relationship to exist in adults and provides further support for a reciprocal relationship between adipocytes and osteoblasts.
Related JoVE Video
Prealbumin is associated with visceral fat mass in patients receiving hemodialysis.
J Ren Nutr
PUBLISHED: 01-27-2013
Show Abstract
Hide Abstract
Albumin and prealbumin are associated with nutritional status and inflammatory status. Each has a residual effect on mortality outcomes when included in regression models that include the other. Prealbumin is increased in the obese mouse model as a consequence of stabilization of prealbumin by retinol binding protein 4 (RBP4) secreted by adipocytes. We carried out this study to establish the contribution of adiposity to prealbumin levels in prevalent patients receiving dialysis and the relationship of prealbumin to RBP4.
Related JoVE Video
Relationships between body roundness with body fat and visceral adipose tissue emerging from a new geometrical model.
Obesity (Silver Spring)
PUBLISHED: 01-21-2013
Show Abstract
Hide Abstract
OBJECTIVE: To develop a new geometrical index that combines height, waist circumference (WC), and hip circumference (HC) and relate this index to total and visceral body fat. DESIGN AND METHODS: Subject data were pooled from three databases that contained demographic, anthropometric, dual energy X-ray absorptiometry (DXA) measured fat mass, and magnetic resonance imaging measured visceral adipose tissue (VAT) volume. Two elliptical models of the human body were developed. Body roundness was calculated from the model using a well-established constant arising from the theory. Regression models based on eccentricity and other variables were used to predict %body fat and %VAT. RESULTS: A body roundness index (BRI) was derived to quantify the individual body shape in a height-independent manner. Body roundness slightly improved predictions of %body fat and %VAT compared to the traditional metrics of body mass index (BMI), WC, or HC. On this basis, healthy body roundness ranges were established. An automated graphical program simulating study results was placed at http://www.pbrc.edu/bodyroundness. CONCLUSION: BRI, a new shape measure, is a predictor of %body fat and %VAT and can be applied as a visual tool for health status evaluations.
Related JoVE Video
Effectiveness of booster seats compared with no restraint or seat belt alone for crash injury prevention.
Acad Emerg Med
PUBLISHED: 01-17-2013
Show Abstract
Hide Abstract
The objective was to evaluate the effectiveness of belt-positioning booster seats, compared with no restraint use and with seat belt use only, during motor vehicle crashes among U.S. children.
Related JoVE Video
Dynamic energy-balance model predicting gestational weight gain.
Am. J. Clin. Nutr.
PUBLISHED: 12-14-2011
Show Abstract
Hide Abstract
Gestational weight gains (GWGs) that exceed the 2009 Institute of Medicine recommended ranges increase risk of long-term postpartum weight retention; conversely, GWGs within the recommended ranges are more likely to result in positive maternal and fetal outcomes. Despite this evidence, recent epidemiologic studies have shown that the majority of pregnant women gain outside the target GWG ranges. A mathematical model that predicts GWG and energy intake could provide a clinical tool for setting precise goals during early pregnancy and continuous objective feedback throughout pregnancy.
Related JoVE Video
A Simple Model Predicting Individual Weight Change in Humans.
J Biol Dyn
PUBLISHED: 11-01-2011
Show Abstract
Hide Abstract
Excessive weight in adults is a national concern with over 2/3 of the US population deemed overweight. Because being overweight has been correlated to numerous diseases such as heart disease and type 2 diabetes, there is a need to understand mechanisms and predict outcomes of weight change and weight maintenance. A simple mathematical model that accurately predicts individual weight change offers opportunities to understand how individuals lose and gain weight and can be used to foster patient adherence to diets in clinical settings. For this purpose, we developed a one dimensional differential equation model of weight change based on the energy balance equation is paired to an algebraic relationship between fat free mass and fat mass derived from a large nationally representative sample of recently released data collected by the Centers for Disease Control. We validate the models ability to predict individual participants weight change by comparing model estimates of final weight data from two recent underfeeding studies and one overfeeding study. Mean absolute error and standard deviation between model predictions and observed measurements of final weights are less than 1.8 ± 1.3 kg for the underfeeding studies and 2.5 ± 1.6 kg for the overfeeding study. Comparison of the model predictions to other one dimensional models of weight change shows improvement in mean absolute error, standard deviation of mean absolute error, and group mean predictions. The maximum absolute individual error decreased by approximately 60% substantiating reliability in individual weight change predictions. The model provides a viable method for estimating individual weight change as a result of changes in intake and determining individual dietary adherence during weight change studies.
Related JoVE Video
Association of increased upper trunk and decreased leg fat with 2-h glucose in control and HIV-infected persons.
Diabetes Care
PUBLISHED: 09-16-2011
Show Abstract
Hide Abstract
Changes in body fat distribution and abnormal glucose metabolism are common in HIV-infected patients. We hypothesized that HIV-infected participants would have a higher prevalence of impaired glucose tolerance (IGT) compared with control subjects.
Related JoVE Video
Relationship between changes in total-body water and fluid distribution with maximal forearm strength in elite judo athletes.
J Strength Cond Res
PUBLISHED: 08-27-2011
Show Abstract
Hide Abstract
Among judo athletes, strong grip strength is crucial for performing offensive and defensive maneuvers that rely predominantly on forearm maximal strength (FMS). The study aims were to evaluate changes in total-body water (TBW) and its compartments (extracellular water [ECW] and intracellular water [ICW]) and their relationship with loss of FMS in elite judo athletes. At baseline (weight stability), 27 male elite athletes were evaluated (age: 23.2 ± 2.8 years) and again evaluated 1-3 days before competition. Athletes were free to gain or lose weight based upon their specific competition needs. Using dilution techniques (deuterium and bromide), TBW and ECW were estimated, and ICW was calculated (ICW = TBW - ECW). Fat, fat-free mass, and appendicular lean soft tissue (LST) were assessed by dual-energy x-ray absorptiometry. Handgrip was used to assess FMS. Using a reduction of 2% as a representative outcome for decreased FMS, 10 athletes were identified as having lost FMS, whereas 17 changed <2% or gained. Comparison of means and logistic regression analysis were performed. Results from baseline to before competition indicated that those who lost ?2% of FMS significantly decreased TBW and ICW by -2.7 ± 3.0 and -4.4 ± 4.2%, respectively. The groups differed in ICW changes (-4.4 ± 4.2 vs. 1.9 ± 6.1%), respectively, for those who lost FMS by ?2%. The ICW changes, but not in TBW or ECW, significantly predicted the risk of losing FMS (? = 0.206; p = 0.027), even adjusting for weight and arm LST changes. These findings indicated that reductions in ICW increased the risk of losing grip strength in elite judo athletes.
Related JoVE Video
Use of balance methods for assessment of short-term changes in body composition.
Obesity (Silver Spring)
PUBLISHED: 08-25-2011
Show Abstract
Hide Abstract
Balance methods reveal changes in body energy, nitrogen, macro- and micronutrients as well as fluid in response to different feeding regimens. Under metabolic ward conditions, where physical activity is restricted and activity and food intake are controlled, the errors of estimates of energy intake, energy expenditure, and energy losses are about 2, 4, and 2%, respectively. Balance techniques can be used to validate techniques of in vivo body composition analysis (BCA). This is necessary since immediate and transient changes in body composition in response to a change in diet adversely affect the validity of techniques by violating the assumptions underlying standard methods (i.e., a constant composition or hydration of lean mass). Using two compartment reference methods, like densitometry, dual X-ray absorptiometry (DXA) or deuterium dilution, changes in fat mass with caloric restriction and overfeeding can be measured with a minimal detectable change (MDC) of 1.0-2.0 kg. However, when compared against balance data, the validity of these techniques to measure short-term changes in body composition is poor. The noninvasive and rapid new quantitative magnetic resonance (QMR) technique has a high precision with a MDC of 0.18 kg of fat mass. The validity of QMR to assess short-term changes in fat mass is challenged by comparison to balance data. Today, techniques used for in vivo BCA should be related to steady state conditions only, while in the nonsteady state, the use of balance methods is recommended to assess short-term changes in body composition.
Related JoVE Video
Evaluation of specific metabolic rates of major organs and tissues: comparison between nonobese and obese women.
Obesity (Silver Spring)
PUBLISHED: 08-11-2011
Show Abstract
Hide Abstract
Elia (1992) identified the specific resting metabolic rates (K(i)) of major organs and tissues in young adults with normal weight: 200 for liver, 240 for brain, 440 for heart and kidneys, 13 for skeletal muscle, 4.5 for adipose tissue and 12 for residual mass (all units in kcal/kg per day). The aim of the present study was to assess the applicability of Elias K(i) values for obese adults. A sample of young women (n = 80) was divided into two groups, nonobese (BMI <29.9 kg/m(2)) and obese (BMI 30.0-43.2 kg/m(2)). This study was based on the mechanistic model: REE = ? (K(i) × T(i)), where REE is whole-body resting energy expenditure measured by indirect calorimetry and T(i) is the mass of individual organs and tissues measured by magnetic resonance imaging. For each organ/tissue, the corresponding Elias K(i) value was analyzed respectively for nonobese and obese groups by using stepwise univariate regression analysis. Elias K(i) values were within the range of 95% confidence intervals (CIs) in the nonobese group. However, Elias K(i) values were outside the right boundaries of 95% CIs in the obese group and a corresponding obesity-adjusted coefficient was calculated as 0.98, indicating that Elias values overestimate K(i) by 2.0% in obese adults. Obesity-adjusted K(i) values were 196 for liver, 235 for brain, 431 for heart and kidneys, 12.7 for skeletal muscle, 4.4 for adipose tissue, and 11.8 for residual mass. In conclusion, although Elias K(i) values were validated in nonobese women, obesity-adjustments are appropriate for application in obese women.
Related JoVE Video
Rate of weight loss can be predicted by patient characteristics and intervention strategies.
J Acad Nutr Diet
PUBLISHED: 07-27-2011
Show Abstract
Hide Abstract
Although dietary weight-loss counseling usually employs a 500 to 1,000 kcal/day energy deficit to induce weight loss of 0.5 to 1 kg/week, this rate of weight loss is rarely achieved in research settings. Biological factors, such as changes in metabolic rate, are partly responsible, but would only account for a small deviation from expected weight loss. There must be other factors, behavioral or related to study design and implementation, that affect the rate of weight loss observed.
Related JoVE Video
Effect of constitution on mass of individual organs and their association with metabolic rate in humans--a detailed view on allometric scaling.
PLoS ONE
PUBLISHED: 07-05-2011
Show Abstract
Hide Abstract
Resting energy expenditure (REE)-power relationships result from multiple underlying factors including weight and height. In addition, detailed body composition, including fat free mass (FFM) and its components, skeletal muscle mass and internal organs with high metabolic rates (i.e. brain, heart, liver, kidneys), are major determinants of REE. Since the mass of individual organs scales to height as well as to weight (and, thus, to constitution), the variance in these associations may also add to the variance in REE. Here we address body composition (measured by magnetic resonance imaging) and REE (assessed by indirect calorimetry) in a group of 330 healthy volunteers differing with respect to age (17-78 years), sex (61% female) and BMI (15.9-47.8 kg/m(2)). Using three dimensional data interpolation we found that the inter-individual variance related to scaling of organ mass to height and weight and, thus, the constitution-related variances in either FFM (model 1) or kidneys, muscle, brain and liver (model 2) explained up to 43% of the inter-individual variance in REE. These data are the first evidence that constitution adds to the complexity of REE. Since organs scale differently as weight as well as height the "fit" of organ masses within constitution should be considered as a further trait.
Related JoVE Video
Cannabinoid-1 receptor inhibition prevents the reduction of 24-hour energy expenditure with weight loss.
Metab. Clin. Exp.
PUBLISHED: 06-06-2011
Show Abstract
Hide Abstract
Pharmacologic inhibition of the cannabinoid-1 receptor (CB1R) in rodent models leads to weight loss and time-dependent changes in energy balance. This study evaluated the effects of CB1R inhibition on weight loss, energy expenditure (EE), and food intake (FI) in an obese canine model following 4 weeks of treatment. Eighteen maintenance-fed obese beagles were evenly and randomly allocated to a CB1R inverse agonist (AM251) (2 mg/kg), a 70% food-restricted (FR) diet, or a control group (C). Evaluations included body weight and composition (dual-energy x-ray absorptiometry scan), EE (doubly labeled water), and FI. Change in body mass at week 4 was significantly greater (P < .050) in the AM251 (-1476.7 g) and FR groups (-1100.0 g) than in the C group (-228.3 g). Food intake was decreased from week 2 onward in the FR and AM251 groups (P < .05). Absolute and lean mass-adjusted EEs were decreased only in the FR group (P < .01); EE in the AM251 group was greater (P < .05) than that in the FR group. Pharmacologic inhibition of CB1R in a canine model led to sustained effects on FI and EE. Weight loss was greater with AM251 than could be accounted for by food restriction (?25%), an effect likely mediated by the EE response to CB1R inhibition.
Related JoVE Video
A survey of the genetics of stomach, liver, and adipose gene expression from a morbidly obese cohort.
Genome Res.
PUBLISHED: 05-20-2011
Show Abstract
Hide Abstract
To map the genetics of gene expression in metabolically relevant tissues and investigate the diversity of expression SNPs (eSNPs) in multiple tissues from the same individual, we collected four tissues from approximately 1000 patients undergoing Roux-en-Y gastric bypass (RYGB) and clinical traits associated with their weight loss and co-morbidities. We then performed high-throughput genotyping and gene expression profiling and carried out a genome-wide association analyses for more than 100,000 gene expression traits representing four metabolically relevant tissues: liver, omental adipose, subcutaneous adipose, and stomach. We successfully identified 24,531 eSNPs corresponding to about 10,000 distinct genes. This represents the greatest number of eSNPs identified to our knowledge by any study to date and the first study to identify eSNPs from stomach tissue. We then demonstrate how these eSNPs provide a high-quality disease map for each tissue in morbidly obese patients to not only inform genetic associations identified in this cohort, but in previously published genome-wide association studies as well. These data can aid in elucidating the key networks associated with morbid obesity, response to RYGB, and disease as a whole.
Related JoVE Video
Decreased limb muscle and increased central adiposity are associated with 5-year all-cause mortality in HIV infection.
AIDS
PUBLISHED: 05-17-2011
Show Abstract
Hide Abstract
Unintentional loss of weight and muscle due to aging and disease has been associated with increased mortality. Wasting and weight loss occur in HIV infection even in the modern era of effective antiretroviral therapy.
Related JoVE Video
Actinic skin damage and mortality--the First National Health and Nutrition Examination Survey Epidemiologic Follow-up Study.
PLoS ONE
PUBLISHED: 04-19-2011
Show Abstract
Hide Abstract
Exposure to sunlight may decrease the risk of several diseases through the synthesis of vitamin D, whereas solar radiation is the main cause of some skin and eye diseases. However, to the best of our knowledge, the association of sun-induced skin damage with mortality remains unknown.
Related JoVE Video
Effects of cell-type specific leptin receptor mutation on leptin transport across the BBB.
Peptides
PUBLISHED: 03-30-2011
Show Abstract
Hide Abstract
The functions of leptin receptors (LRs) are cell-type specific. At the blood-brain barrier, LRs mediate leptin transport that is essential for its CNS actions, and both endothelial and astrocytic LRs may be involved. To test this, we generated endothelia specific LR knockout (ELKO) and astrocyte specific LR knockout (ALKO) mice. ELKO mice were derived from a cross of Tie2-cre recombinase mice with LR-floxed mice, whereas ALKO mice were generated by a cross of GFAP-cre with LR-floxed mice, yielding mutant transmembrane LRs without signaling functions in endothelial cells and astrocytes, respectively. The ELKO mutation did not affect leptin half-life in blood or apparent influx rate to the brain and spinal cord, though there was an increase of brain parenchymal uptake of leptin after in situ brain perfusion. Similarly, the ALKO mutation did not affect blood-brain barrier permeation of leptin or its degradation in blood and brain. The results support our observation from cellular studies that membrane-bound truncated LRs are fully efficient in transporting leptin, and that basal levels of astrocytic LRs do not affect leptin transport across the endothelial monolayer. Nonetheless, the absence of leptin signaling at the BBB appears to enhance the availability of leptin to CNS parenchyma. The ELKO and ALKO mice provide new models to determine the dynamic regulation of leptin transport in metabolic and inflammatory disorders where cellular distribution of LRs is shifted.
Related JoVE Video
Relationship between abdominal fat and bone mineral density in white and African American adults.
Bone
PUBLISHED: 02-26-2011
Show Abstract
Hide Abstract
Several studies have documented relationships between adipose tissue and bone mineral density (BMD); however, the degree to which there are racial differences in this relationship is not known. The purpose of this study was to examine the relationships between abdominal visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) and BMD among white and African American adults. The sample included 330 white women, 328 African American women, 307 white men, and 116 African American men 18-74 years of age. Dual-energy X-ray absorptiometry scans were used to measure BMD and computed tomography scans were used to measure abdominal VAT and SAT. Linear regression was used to assess the relationships between abdominal adiposity and BMD and to explore possible sex and race differences in the associations. In the total sample as well as in all sex-by-race groups, VAT and SAT were negatively related to BMD, after adjustment for lean body mass (LBM) and several covariates. The VAT model (including covariates) explained 33.3% of the variance in BMD and the SAT model (including covariates) explained 32.7% of the variance in BMD. Being African American, being male, and having high LBM were all associated with higher BMD. Race and sex interactions were not significant, indicating that the relationships were similar across race and sex groups. In conclusion, BMD was inversely related to abdominal VAT and SAT in white and African American adults after adjustment for LBM.
Related JoVE Video
Age-related skeletal muscle decline is similar in HIV-infected and uninfected individuals.
J. Gerontol. A Biol. Sci. Med. Sci.
PUBLISHED: 02-10-2011
Show Abstract
Hide Abstract
Skeletal muscle (SM) mass decreases with advanced age and with disease in HIV infection. It is unknown whether age-related muscle loss is accelerated in the current era of antiretroviral therapy and which factors might contribute to muscle loss among HIV-infected adults. We hypothesized that muscle mass would be lower and decline faster in HIV-infected adults than in similar-aged controls.
Related JoVE Video
Scaling of body composition to height: relevance to height-normalized indexes.
Am. J. Clin. Nutr.
PUBLISHED: 01-19-2011
Show Abstract
Hide Abstract
Body weight scales to height with a power of ?2, thus forming the basis of body mass index (weight/height(2)). The corresponding scaling of body composition to height has not been established in a representative sample of US adults.
Related JoVE Video
Are adult body circumferences associated with height? Relevance to normative ranges and circumferential indexes.
Am. J. Clin. Nutr.
PUBLISHED: 12-01-2010
Show Abstract
Hide Abstract
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.
Related JoVE Video
Canaries in the coal mine: a cross-species analysis of the plurality of obesity epidemics.
Proc. Biol. Sci.
PUBLISHED: 11-24-2010
Show Abstract
Hide Abstract
A dramatic rise in obesity has occurred among humans within the last several decades. Little is known about whether similar increases in obesity have occurred in animals inhabiting human-influenced environments. We examined samples collectively consisting of over 20 000 animals from 24 populations (12 divided separately into males and females) of animals representing eight species living with or around humans in industrialized societies. In all populations, the estimated coefficient for the trend of body weight over time was positive (i.e. increasing). The probability of all trends being in the same direction by chance is 1.2 × 10(-7). Surprisingly, we find that over the past several decades, average mid-life body weights have risen among primates and rodents living in research colonies, as well as among feral rodents and domestic dogs and cats. The consistency of these findings among animals living in varying environments, suggests the intriguing possibility that the aetiology of increasing body weight may involve several as-of-yet unidentified and/or poorly understood factors (e.g. viral pathogens, epigenetic factors). This finding may eventually enhance the discovery and fuller elucidation of other factors that have contributed to the recent rise in obesity rates.
Related JoVE Video
A computational model to determine energy intake during weight loss.
Am. J. Clin. Nutr.
PUBLISHED: 10-20-2010
Show Abstract
Hide Abstract
Energy intake (EI) during weight loss is difficult and costly to measure accurately.
Related JoVE Video
Specific metabolic rates of major organs and tissues across adulthood: evaluation by mechanistic model of resting energy expenditure.
Am. J. Clin. Nutr.
PUBLISHED: 10-20-2010
Show Abstract
Hide Abstract
The specific resting metabolic rates (K(i); in kcal · kg(-1 )· d(-1)) of major organs and tissues in adults were suggested by Elia (in Energy metabolism: tissue determinants and cellular corollaries. New York, NY: Raven Press, 1992) to be as follows: 200 for liver, 240 for brain, 440 for heart and kidneys, 13 for skeletal muscle, 4.5 for adipose tissue, and 12 for residual organs and tissues. However, Elias K(i) values have never been fully evaluated.
Related JoVE Video
Comparison of dual-energy x-ray absorptiometric and anthropometric measures of adiposity in relation to adiposity-related biologic factors.
Am. J. Epidemiol.
PUBLISHED: 10-15-2010
Show Abstract
Hide Abstract
Dual-energy x-ray absorptiometry (DXA) can provide accurate measurements of body composition. Few studies have compared the relative validity of DXA measures with anthropometric measures such as body mass index (BMI) and waist circumference (WC). The authors compared correlations of DXA measurements of total fat mass and fat mass percent in the whole body and trunk, BMI, and WC with obesity-related biologic factors, including blood pressure and levels of plasma lipids, C-reactive protein, and fasting insulin and glucose, among 8,773 adults in the National Health and Nutrition Examination Survey (1999-2004). Overall, the magnitudes of correlations of BMI and WC with the obesity-related biologic factors were similar to those of fat mass or fat mass percent in the whole body and trunk, respectively. These observations were largely consistent across different age, gender, and ethnic groups. In addition, in both men and women, BMI and WC demonstrated similar abilities to distinguish between participants with and without the metabolic syndrome in comparison with corresponding DXA measurements. These data indicate that the validity of simple anthropometric measures such as BMI and WC is comparable to that of DXA measurements of fat mass and fat mass percent, as evaluated by their associations with obesity-related biomarkers and prevalence of metabolic syndrome.
Related JoVE Video
Evaluation of specific metabolic rates of major organs and tissues: comparison between men and women.
Am. J. Hum. Biol.
PUBLISHED: 08-18-2010
Show Abstract
Hide Abstract
The specific resting metabolic rates (K(i) , in kcal/kg per day) of major organs and tissues in the Reference Man were suggested in 1992 by Elia: 200 for liver, 240 for brain, 440 for heart and kidneys, 13 for skeletal muscle, 4.5 for adipose tissue and 12 for the residual mass. However, it is unknown whether gender influences the K(i) values. The aim of the present study was to compare the K(i) values observed in nonelderly nonobese men to the corresponding values in women.
Related JoVE Video
Is there evidence for a set point that regulates human body weight?
F1000 Med Rep
PUBLISHED: 08-09-2010
Show Abstract
Hide Abstract
There is evidence for the idea that there is biological (active) control of body weight at a given set point. Body weight is the product of genetic effects (DNA), epigenetic effects (heritable traits that do not involve changes in DNA), and the environment. Regulation of body weight is asymmetric, being more effective in response to weight loss than to weight gain. However, regulation may be lost or camouflaged by Western diets, suggesting that the failure of biological control is due mainly to external factors. In this situation, the bodys set point (i.e., a constant body-inherent weight regulated by a proportional feedback control system) is replaced by various settling points that are influenced by energy and macronutrient intake in order for the body to achieve a zero energy balance. In a world of abundance, a prudent lifestyle and thus cognitive control are preconditions of effective biological control and a stable body weight. This idea also impacts future genetic research on body weight regulation. Searching for the genetic background of excess weight gain in a world of abundance is misleading since the possible biological control is widely overshadowed by the effect of the environment. In regard to clinical practice, dietary approaches to both weight loss and weight gain have to be reconsidered. In underweight patients (e.g., patients with anorexia nervosa), weight gain is supported by biological mechanisms that may or may not be suppressed by hyperalimentation. To overcome weight loss-induced counter-regulation in the overweight, biological signals have to be taken into account. Computational modeling of weight changes based on metabolic flux and its regulation will provide future strategies for clinical nutrition.
Related JoVE Video
Intermuscular adipose tissue and metabolic associations in HIV infection.
Obesity (Silver Spring)
PUBLISHED: 06-10-2010
Show Abstract
Hide Abstract
Intermuscular adipose tissue (IMAT) is associated with metabolic abnormalities similar to those associated with visceral adipose tissue (VAT). Increased IMAT has been found in obese human immunodeficiency virus (HIV)-infected women. We hypothesized that IMAT, like VAT, would be similar or increased in HIV-infected persons compared with healthy controls, despite decreases in subcutaneous adipose tissue (SAT) found in HIV infection. In the second FRAM (Study of Fat Redistribution and Metabolic Change in HIV infection) exam, we studied 425 HIV-infected subjects and 211 controls (from the Coronary Artery Risk Development in Young Adults study) who had regional AT and skeletal muscle (SM) measured by magnetic resonance imaging (MRI). Multivariable linear regression identified factors associated with IMAT and its association with metabolites. Total IMAT was 51% lower in HIV-infected participants compared with controls (P = 0.003). The HIV effect was attenuated after multivariable adjustment (to -28%, P < 0.0001 in men and -3.6%, P = 0.70 in women). Higher quantities of leg SAT, upper-trunk SAT, and VAT were associated with higher IMAT in HIV-infected participants, with weaker associations in controls. Stavudine use was associated with lower IMAT and SAT, but showed little relationship with VAT. In multivariable analyses, regional IMAT was associated with insulin resistance and triglycerides (TGs). Contrary to expectation, IMAT is not increased in HIV infection; after controlling for demographics, lifestyle, VAT, SAT, and SM, HIV(+) men have lower IMAT compared with controls, whereas values for women are similar. Stavudine exposure is associated with both decreased IMAT and SAT, suggesting that IMAT shares cellular origins with SAT.
Related JoVE Video
Between-slice intervals in quantification of adipose tissue and muscle in children.
Int J Pediatr Obes
PUBLISHED: 06-07-2010
Show Abstract
Hide Abstract
Magnetic Resonance Imaging (MRI) is increasingly being used in children to quantify adipose tissue (AT) and skeletal muscle (SM) in vivo. It is unclear whether the every 5 cm whole body MRI protocol used in adults is appropriate when applied in children. Whole body MRI continuous 1 cm thick slices were acquired in 73, aged 5-17-year-old healthy children. Images were segmented into subcutaneous (SAT), visceral (VAT), intermuscular AT (IMAT), and SM. The percentage difference between volumes measured by the continuous protocol and volumes estimated with protocols of different between-slice intervals (i.e., interval = 2, 3, 4 and 5 cm) was larger with an increase in interval size, depot size, weight and body mass index percentile. For group comparisons, studies will require less than 5.4% more subjects if an every 5 cm protocol is used for equivalent power as the every 1 cm protocol. For individual subject comparisons, interval protocols can be used to reliably distinguish between subjects who differ in SM or SAT volume by 0.14 to 0.64 L (i.e., 1 to 5% of SM or SAT volume) or more, or in VAT or IMAT volume by 0.06 to 0.21 L (i.e., 10 to 30% of VAT or IMAT volume) or more. The every 5 cm image acquisition protocol can be considered as accurate as the contiguous protocol for group comparisons in children, as well as for comparison of SM and SAT among individual children. However, a smaller slice interval protocol would be more accurate for comparison of VAT or IMAT among individual children.
Related JoVE Video
Regional adipose tissue measured by MRI over 5 years in HIV-infected and control participants indicates persistence of HIV-associated lipoatrophy.
AIDS
PUBLISHED: 05-27-2010
Show Abstract
Hide Abstract
Peripheral fat loss and visceral fat gain have been reported in HIV infection. There are limited data on long-term change in adipose tissue in HIV-infected patients vs. controls. Therefore, we determined change in regional adipose tissue from baseline examination to 5 years later among participants in the study of Fat Redistribution and Metabolic Change in HIV Infection.
Related JoVE Video
Greater lean tissue and skeletal muscle mass are associated with higher bone mineral content in children.
Nutr Metab (Lond)
PUBLISHED: 05-11-2010
Show Abstract
Hide Abstract
To compare the relationship of skeletal muscle mass with bone mineral content in an ethnically diverse group of 6 to 18 year old boys and girls.
Related JoVE Video
Quantitative magnetic resonance fat measurements in humans correlate with established methods but are biased.
Obesity (Silver Spring)
PUBLISHED: 05-06-2010
Show Abstract
Hide Abstract
Precision and accuracy of the quantitative magnetic resonance (QMR) system for measuring fat in phantoms and total body fat (TBF) in humans were investigated. Measurements were made using phantoms: oil, beef with water, beef with oil, and humans with oil and water. TBF(QMR) in humans was compared with TBF by a four-compartment model (TBF(4C)). The coefficient of variation (CV) for replicate TBF(QMR) was 0.437%. QMR fat was lower at 23 °C vs. 37 °C. The fat increase in QMR phantom studies was consistent with the oil increase. When oil was added with humans, the increase in TBF(QMR) was >250 g for the initial 250 g of oil. With additional oil increments, the increase in TBF(QMR) was consistent with the amount of oil added. When water was added with humans, the TBF(QMR) increased independent of the amount of water added. TBF(QMR) was significantly less (mean ± s.e.) than TBF(4C) (females: -0.68 ± 0.27 kg, males: -4.66 ± 0.62 kg; P = 0.0001), TBF(BV) (females: -1.90 ± 0.40 kg; males: -5.68 ± 0.75 kg; P = 0.0001), and TBF(D2O) for males, but greater for females (1.19 ± 0.43 kg vs. -3.69 ± 0.81 kg for males; P = 0.0003). TBF(QMR) was lower than TBF(iDXA) with the difference greater in males (P = 0.001) and decreased with age (P = 0.011). The strong linear relationships between TBF(QMR) and TBF(4C), TBF(BV), and TBF(D2O) with slopes consistent with unity suggest that modifications are required to improve the accuracy. Should the latter be accomplished, QMR holds promise as a highly precise, rapid, and safe, noninvasive method for estimating the amount of and changes in TBF in overweight and severely obese persons.
Related JoVE Video
Estimation of percentage body fat by dual-energy x-ray absorptiometry: evaluation by in vivo human elemental composition.
Phys Med Biol
PUBLISHED: 04-14-2010
Show Abstract
Hide Abstract
Dual-energy x-ray absorptiometry (DXA) is widely applied for estimating body fat. The percentage of body mass as fat (%fat) is predicted from a DXA-estimated R(ST) value defined as the ratio of soft tissue attenuation at two photon energies (e.g., 40 keV and 70 keV). Theoretically, the R(ST) concept depends on the mass of each major element in the human body. The DXA R(ST) values, however, have never been fully evaluated by measured human elemental composition. The present investigation evaluated the DXA R(ST) value by the total body mass of 11 major elements and the DXA %fat by the five-component (5C) model, respectively. Six elements (i.e. C, N, Na, P, Cl and Ca) were measured by in vivo neutron activation analysis, and potassium (i.e. K) by whole-body (40)K counting in 27 healthy adults. Models were developed for predicting the total body mass of four additional elements (i.e. H, O, Mg and S). The elemental content of soft tissue, after correction for bone mineral elements, was used to predict the R(ST) values. The DXA R(ST) values were strongly associated with the R(ST) values predicted from elemental content (r = 0.976, P < 0.001), although there was a tendency for the elemental-predicted R(ST) to systematically exceed the DXA-measured R(ST) (mean +/- SD, 1.389 +/- 0.024 versus 1.341 +/- 0.024). DXA-estimated %fat was strongly associated with 5C %fat (24.4 +/- 12.0% versus 24.9 +/- 11.1%, r = 0.983, P < 0.001). DXA R(ST) is evaluated by in vivo elemental composition, and the present study supports the underlying physical concept and accuracy of the DXA method for estimating %fat.
Related JoVE Video
A randomized trial of lifestyle modification and taranabant for maintaining weight loss achieved with a low-calorie diet.
Obesity (Silver Spring)
PUBLISHED: 04-08-2010
Show Abstract
Hide Abstract
Improving the maintenance of weight loss remains a critical challenge for obesity researchers. The present 1-year, randomized, placebo-controlled trial evaluated the safety and efficacy of weight maintenance counseling combined with either placebo or the cannabinoid-1 receptor inverse agonist, taranabant, for sustaining prior weight loss achieved on a low-calorie diet (LCD). Seven hundred eighty-four individuals who had lost ? 6% of body weight during six initial weeks of treatment with an 800 kcal/day liquid LCD were randomly assigned to placebo or once-daily taranabant in doses of 0.5, 1, or 2 mg. All participants were provided monthly, on-site behavioral weight maintenance counseling, as well as monthly phone calls. The primary end point was change in body weight from randomization to week 52. The randomized participants lost an average of 9.6 kg (9.5% of initial weight) during the 6-week LCD. The model-adjusted mean change in body weight during the subsequent 1 year was +1.7 kg for placebo, compared with -0.1, -0.6, and -1.2 kg for the taranabant 0.5, 1, and 2 mg doses, respectively (all P values ? 0.007 vs. placebo). The incidences of psychiatric-related adverse events, including irritability, were higher for taranabant 1 and 2 mg vs. placebo (P ? 0.038). In addition to reporting data on the safety and efficacy of taranabant, this study provides a method for studying the combination of lifestyle modification and pharmacotherapy for weight maintenance after diet-induced weight loss.
Related JoVE Video
BMI and risk of serious upper body injury following motor vehicle crashes: concordance of real-world and computer-simulated observations.
PLoS Med.
PUBLISHED: 02-17-2010
Show Abstract
Hide Abstract
Men tend to have more upper body mass and fat than women, a physical characteristic that may predispose them to severe motor vehicle crash (MVC) injuries, particularly in certain body regions. This study examined MVC-related regional body injury and its association with the presence of driver obesity using both real-world data and computer crash simulation.
Related JoVE Video
Accuracy of DXA in estimating body composition changes in elite athletes using a four compartment model as the reference method.
Nutr Metab (Lond)
PUBLISHED: 01-26-2010
Show Abstract
Hide Abstract
Dual-energy x-ray absorptiometry (DXA) provides an affordable and practical assessment of multiple whole body and regional body composition. However, little information is available on the assessment of changes in body composition in top-level athletes using DXA. The present study aimed to assess the accuracy of DXA in tracking body composition changes (relative fat mass [%FM], absolute fat mass [FM], and fat-free mass [FFM]) of elite male judo athletes from a period of weight stability to prior to a competition, compared to a four compartment model (4C model), as the criterion method.
Related JoVE Video
New fat free mass - fat mass model for use in physiological energy balance equations.
Nutr Metab (Lond)
PUBLISHED: 01-25-2010
Show Abstract
Hide Abstract
The Forbes equation relating fat-free mass (FFM) to fat mass (FM) has been used to predict longitudinal changes in FFM during weight change but has important limitations when paired with a one dimensional energy balance differential equation. Direct use of the Forbes model within a one dimensional energy balance differential equation requires calibration of a translate parameter for the specific population under study. Comparison of translates to a representative sample of the US population indicate that this parameter is a reflection of age, height, race and gender effects.
Related JoVE Video
A cellular level approach to predicting resting energy expenditure: Evaluation of applicability in adolescents.
Am. J. Hum. Biol.
PUBLISHED: 01-09-2010
Show Abstract
Hide Abstract
We previously derived a cellular level approach for a whole-body resting energy expenditure (REE) prediction model by using organ and tissue mass measured by magnetic resonance imaging (MRI) combined with their individual cellularity and assumed stable-specific resting metabolic rates. Although this approach predicts REE well in both young and elderly adults, there were no studies in adolescents that specifically evaluated REE in relation to organ-tissue mass. It is unclear whether the approach can be applied to rapidly growing adolescents. The aim of the present study was to evaluate the applicability of the previous developed REE prediction model in adolescents, and to compare its applicability in young and elderly adults. Specifically, we tested the hypothesis that measured REE can be predicted from a combination of individual organ and tissue mass and their related cellularity. This was a 2-year longitudinal investigation. Twenty healthy male subjects with a mean age of 14.7 years had REE, organ and tissue mass, body cell mass, and fat-free mass (FFM) measured by indirect calorimetry, whole-body MRI, whole-body (40)K counting and dual-energy X-ray absorptiometry, respectively. The predicted REE (REEp; mean +/- SD, 1,487 +/- 238 kcal/day) was correlated with the measured REE (REEm, 1,606 +/- 237 kcal/day, r = 0.76, P < 0.001). The mean difference (118 +/- 165 kcal/day) between REEm and REEp was significant (P = 0.0047), accounting for 7.3% of REEm for the entire group. The present study, the first of its type in adolescents, does not support the applicability of the organ-tissue-based REE prediction model during rapid adolescent growth. A modified general REE prediction model is thus suggested which may account for the higher REE/FFM ratio observed in adolescents.
Related JoVE Video
Meal replacements and energy balance.
Physiol. Behav.
PUBLISHED: 01-04-2010
Show Abstract
Hide Abstract
Induction and maintenance of a period of negative energy balance are required for overweight and obese subjects to lose weight. Meal replacements, particularly in beverage form, have now evolved as part of the "toolbox" used by researchers and clinicians to achieve negative energy balance. This overview traces the historical development of beverage meal replacements, reviews key studies supporting their clinical efficacy, and examines concerns related to their safe use. This collective information supports the view that meal replacements, particularly in beverage form, are now an effective and safe component for use in the clinical setting. Further studies are needed to identify those subjects most likely to benefit from use of meal replacements as part of their comprehensive weight control program.
Related JoVE Video
Lifestyle interventions for the treatment of class III obesity: a primary target for nutrition medicine in the obesity epidemic.
Am. J. Clin. Nutr.
PUBLISHED: 11-11-2009
Show Abstract
Hide Abstract
Although rates of obesity have increased universally in the United States over the past 30 y, it is clear that certain individuals are more susceptible to weight gain than others. Extreme obesity [body mass index (in kg/m(2)) > 40] is increasing at rates greater than any other class of obesity in the United States. Severely obese patients often suffer from a wide variety of comorbidities. Although weight-loss surgery is the most effective treatment, it offers little in the way of large-scale containment due to its costly and invasive nature. Lifestyle interventions that induce modest weight loss and improve fitness can significantly lower disease risk. As medical professionals in the field of nutrition, we must focus first on the patient cohort that suffers most from the modern obesogenic environment. Lifestyle interventions specifically targeted toward the class III obese cohort should be a high priority in nutrition medicine.
Related JoVE Video
Obesity and functional impairment: influence of comorbidity, joint pain, and mental health.
Obesity (Silver Spring)
PUBLISHED: 11-05-2009
Show Abstract
Hide Abstract
To examine the relationship between obesity and functional impairment and the influence of comorbidity, joint pain, and mental health on this association, we used US adult respondents (N = 430,912) to the 2007 Behavioral Risk Factor Surveillance Survey (BRFSS-07). Functional impairment was indicated if a respondent was either (i) limited in any way or in any activities because of physical, mental, or emotional problems, or (ii) had any health problem that required using special equipment such as a cane, wheelchair, special bed, or special telephone. Approximately 62.8% of respondents were overweight or obese and 20.3% were functionally impaired. The unadjusted relationship between obesity and functional impairment revealed a classical J-shaped pattern with odds ratios (95% confidence interval) compared to the normal weight group: 1.63 (1.54-1.73), 1.22 (1.20-1.25), 1.77 (1.73-1.81), 2.43 (2.36-2.51), and 4.12 (3.97-4.27) for underweight, overweight, obesity class I, II, and III, respectively. Although inclusion of different combinations of sociodemographic and medical covariates substantially attenuated the unadjusted association, the collective inclusion of all covariates in a single model did not eliminate the significant J-shaped association resulting in the following corresponding adjusted odds ratios: 1.19 (1.13-1.25), 1.01 (0.99-1.04), 1.23 (1.19-1.27), 1.38 (1.32-1.44), and 1.92 (1.82-2.02). The attenuation was mostly influenced by medical comorbidity. In conclusion, functional impairment is associated with obesity, primarily due to medical comorbidity conditions. The significant residual association highlights the importance of sustainable obesity prevention and treatment at both the individual and public level as functional impairment can create burdens at individual, familial, and societal levels.
Related JoVE Video
Insomnia and sleep duration as mediators of the relationship between depression and hypertension incidence.
Am. J. Hypertens.
PUBLISHED: 11-05-2009
Show Abstract
Hide Abstract
Depression has been found to predict the incidence of hypertension and other adverse cardiovascular events in prospective studies. Insomnia and short sleep duration, which are typical symptoms of depression, have also been shown to increase the risk for hypertension incidence. Insomnia is associated with increased activation of the hypothalamic-pituitary-adrenal axis, and short sleep duration raises average 24-h blood pressure, which over time could lead to structural adaptations that gradually reset the entire cardiovascular system to operate at an elevated pressure equilibrium. No previous published population studies have examined whether insomnia and sleep duration mediate the relationship between depression and hypertension incidence.
Related JoVE Video
Adipose tissue distribution after weight restoration and weight maintenance in women with anorexia nervosa.
Am. J. Clin. Nutr.
PUBLISHED: 09-30-2009
Show Abstract
Hide Abstract
Body image distortions are a core feature of anorexia nervosa (AN). We, and others, previously reported abnormalities in adipose tissue distribution after acute weight restoration in adult women with AN compared with body mass index-matched healthy control women. Whether these abnormalities persist over time remains unknown.
Related JoVE Video
Contribution of individual organ mass loss to weight loss-associated decline in resting energy expenditure.
Am. J. Clin. Nutr.
PUBLISHED: 08-26-2009
Show Abstract
Hide Abstract
Weight loss leads to reduced resting energy expenditure (REE) independent of fat-free mass (FFM) and fat mass (FM) loss, but the effect of changes in FFM composition is unclear.
Related JoVE Video
Missing data in randomized clinical trials for weight loss: scope of the problem, state of the field, and performance of statistical methods.
PLoS ONE
PUBLISHED: 08-13-2009
Show Abstract
Hide Abstract
Dropouts and missing data are nearly-ubiquitous in obesity randomized controlled trails, threatening validity and generalizability of conclusions. Herein, we meta-analytically evaluate the extent of missing data, the frequency with which various analytic methods are employed to accommodate dropouts, and the performance of multiple statistical methods.
Related JoVE Video
Relationship between adiposity and cardiovascular risk factors in prevalent hemodialysis patients.
J Ren Nutr
PUBLISHED: 07-10-2009
Show Abstract
Hide Abstract
Increased body mass index (BMI) is associated with reduced all-cause and cardiovascular (CV) mortality in hemodialysis (HD) patients, whereas CV risk increases with BMI in the general population. In the general population, obesity is associated with inflammation, decreased high-density lipoprotein (HDL) cholesterol, increased low-density lipoprotein (LDL) cholesterol, and triglycerides (TGs), all risk factors for CV disease. Low-density lipoprotein cholesterol does not predict CV risk in HD, whereas increased C-reactive protein and interleukin-6 (IL-6), low HDL and apolipoprotein (apo) AI, and increased fasting TGs do predict risk. Renal failure is associated with dyslipidemia and inflammation in normal-weight patients. We hypothesized that the effects of obesity may be obscured by renal failure in HD.
Related JoVE Video

What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.