bluuebunny/crossref_metadata_2025 huggingface dataset:
Pathways to Obesity Prevention: Report of a National Institutes of Health Workshop1
Authors: Kumanyika Shiriki K. , Obarzanek Eva
Published: April 2008

There is an extensive research base on obesity treatment and on the health benefits of weight loss, but relatively little research has focused on obesity prevention. This article summarizes results of a workshop conducted by investigators funded under a National Institutes of Health initiative designed to stimulate novel research for obesity prevention. The 20 pilot studies funded under this initiative involved study populations that were diverse with respect to life stage and ethnicity, were conducted in a variety of natural and research settings, and involved a mix of interventions, including face‐to‐face group and individual counseling, as well as mail, telephone, and internet‐based approaches. The workshop, which occurred approximately halfway through the 3‐year funding period, emphasized concepts and experiences related to initiating and conducting obesity prevention studies. Investigators discussed theoretical perspectives as well as various challenges encountered, for example, in study implementation in different clinical and community settings, in working with children and families, and in studying pregnant and postpartum women. Other topics discussed included the difficulty of motivating individuals for prevention of weight gain, relevant cultural and racial/ethnic considerations, and the particular need for valid and practical measures of energy balance, body composition, and physical fitness in obesity prevention research. A key conclusion was that using obesity treatment as the primary paradigm may be a limiting perspective for considering obesity prevention issues. Further insights derived from the workshop deliberations are reflected in a detailed list of recommendations for future obesity prevention research.
Variance‐Component Analysis of Obesity in Type 2 Diabetes Confirms Loci on Chromosomes 1q and 11q
Authors: van Tilburg Jonathan H.O. , Sandkuijl Lodewijk A. , Strengman Eric , Pearson Peter L. , van Haeften Timon W. , Wijmenga Cisca
Published: April 2008

To study genetic loci influencing obesity in nuclear families with type 2 diabetes, we performed a genome‐wide screen with 325 microsatellite markers that had an average spacing of 11 cM and a mean heterozygosity of ∼75% covering all 22 autosomes. Genotype data were obtained from 562 individuals from 178 families from the Breda Study Cohort. These families were determined to have at least two members with type 2 diabetes. As a measure of obesity, the BMI of each diabetes patient was determined. The genotypes were analyzed using variance components (VCs) analysis implemented in GENEHUNTER 2 to determine quantitative trait loci influencing BMI. The VC analysis revealed two genomic regions showing VC logarithm of odds (LOD) scores ≥1.0 on chromosome 1 and chromosome 11. The regions of interest on both chromosomes were further investigated by fine‐mapping with additional markers, resulting in a VC LOD score of 1.5 on chromosome 1q and a VC LOD of 2.4 on chromosome 11q. The locus on chromosome 1 has been implicated previously in diabetes. The locus on chromosome 11 has been implicated previously in diabetes and obesity. Our study to determine linkage for BMI confirms the presence of quantitative trait loci influencing obesity in subjects with type 2 diabetes on chromosomes 1q31‐q42 and 11q14‐q24.
Moderate Exercise and Fibrinolytic Potential in Obese Sedentary Men with Metabolic Syndrome
Authors: Morris Penelope J. , Packianathan C. Ira , van Blerk Catherine J. , Finer Nicholas
Published: April 2008

Objective: To investigate the impact of 30‐minute walking exercise at 70% Vo2max on tissue plasminogen activator (t‐PA) Ag and plasminogen activator inhibitor type 1 (PAI‐1) Ag in obese sedentary males.

Research Methods and Procedures: A controlled observational study of the effect of a 30‐minute acute exercise bout at 70% Vo2max on plasma t‐PA antigen and PAI‐1 antigen in 10 obese sedentary males matched for age, ethnic origin, and smoking status with 10 nonobese sedentary male controls.

Results: The obese group remained hypofibrinolytic compared with the nonobese group at all time‐points before, during, and after exercise. t‐PA increased in both groups with exercise before returning to baseline values 30 minutes after exercise. PAI‐1 did not significantly change in either group with exercise but rose significantly 30 minutes after exercise in the obese group.

Discussion: The reduction in fibrinolytic potential in the obese group represents an increase in acute thrombotic risk and could account for the increased incidence of exercise‐associated myocardial infarction observed in sedentary obese groups.
Normal Distribution of Body Weight Gain in Male Sprague‐Dawley Rats Fed a High‐Energy Diet
Authors: Archer Zoe A. , Rayner D. Vernon , Rozman Jan , Klingenspor Martin , Mercer Julian G.
Published: April 2008

Objective: To investigate the effect of a high‐energy (HE) diet on caloric intake, body weight, and related parameters in outbred male Sprague‐Dawley (SD) rats.

Research Methods and Procedures: Twenty‐eight SD rats were fed either chow (C) for 19 weeks or HE diet for 14 weeks and then C for 5 weeks. Blood hormones and metabolites were assayed, and expression of uncoupling protein‐1 and hypothalamic energy‐balance‐related genes were determined by Northern blotting and in situ hybridization, respectively.

Results: HE rats gained body weight more rapidly than C animals with a range of weight gains, but there was no evidence that weight gain was bimodally distributed. Caloric intake was transiently elevated after introduction of the HE diet. Transfer of HE rats back to C resulted in a drop in caloric intake, but a stable body weight. In terminal analysis, two of four dissected adipose tissue depots were heavier in rats that had previously been fed HE diet. Blood leptin, insulin, glucose, and nonesterified fatty acids were not different between the groups. Uncoupling protein‐1 mRNA was elevated in interscapular brown adipose tissue from HE rats. There was a trend for agouti‐related peptide mRNA in the hypothalamic arcuate nucleus to be higher in HE rats.

Discussion: Contrary to other studies of the SD rat on HE diet, body weight and other measured parameters were normally distributed. There was no segregation into two distinct populations on the basis of susceptibility to diet‐induced obesity. This characteristic may be dependent on the breeding colony from which animals were sourced.
Lower Serum Adiponectin Levels in African‐American Boys
Authors: Degawa‐Yamauchi Mikako , Dilts Jason R. , Bovenkerk Jason E. , Saha Chandan , Pratt J. Howard , Considine Robert V.
Published: April 2008

Objective: To examine adiponectin, an adipocyte‐secreted hormone with anti‐inflammatory and insulin‐sensitizing effects, in relation to race or gender in younger subjects.

Research Methods and Procedures: The relationship of adiponectin, quantitated by radioimmunoassay, to anthropometric and metabolic factors (fasting insulin, glucose, and leptin) and reproductive hormones was examined in 46 healthy African Americans (25 girls/21 boys) and 40 whites (20 girls/20 boys) ranging in age from 12 to 21 years.

Results: There was no statistical difference in BMI or in BMI percentile among the four groups. Sums of skinfolds, but not skinfold percentile, were significantly lower in boys than girls (p = 0.001 and p = 0.896, respectively), whereas there was no difference between racial groups. Leptin was significantly greater in girls (p = 0.0002). There was no difference in fasting serum glucose, insulin, or homeostasis model assessment score among any of the groups. There was a significant negative univariate relationship between serum adiponectin and both BMI and BMI percentile for the entire group (p = 0.006 and p = 0.005). In a multivariate model, BMI percentile (p = 0.005) and the interaction between race and gender (p = 0.026) were significant predictors of serum adiponectin. In this model, African‐American boys had the lowest serum adiponectin level, 37% less than white boys, who had the highest adiponectin levels.

Discussion: Serum adiponectin levels are reduced in young obese subjects (African Americans and whites) and are lower in African‐American boys than white boys. A lower adiponectin level in African‐American boys may predispose this group to a greater risk of diabetes and cardiovascular disease.
Diet, Obesity, and Hyperglycemia in LG/J and SM/J Mice
Authors: Ehrich Thomas H. , Kenney Jane P. , Vaughn Ty T. , Pletscher L. Susan , Cheverud James M.
Published: April 2008

Objective: To examine the differential response of obesity‐ and diabetes‐related traits to a high‐ or low‐fat diet in LG/J and SM/J mice. We also examined food consumption in these strains.

Research Methods and Procedures: Mice were placed on a high‐ or low‐fat diet after weaning. Animals were weighed once per week and subjected to glucose tolerance tests at 20 weeks. At sacrifice, fat pads and internal organs were removed along with serum samples. For food consumption, LG/J and SM/J mice of each sex were assigned to a high‐fat or low‐fat diet after reaching maturity. Mice were weighed three times per week, and food consumed was determined by subtraction.

Results: LG/J animals consume more total food, but SM/J animals consume more food per gram of body weight. LG/J mice grow faster to 10 weeks but slower from 10 to 20 weeks, have higher cholesterol and free fatty acid levels, and have lower basal glucose levels and better response to a glucose challenge than SM/J mice. For most traits, SM/J mice respond more strongly to a high‐fat diet than LG/J mice, including body weight and growth, basal glucose levels, organ weights, fat distribution, and circulating triglycerides and cholesterol levels.

Discussion: Obesity‐related phenotypes, as well as response to increased dietary fat, differ genetically between LG/J and SM/J and can, therefore, be mapped. This study indicates that the cross of SM/J and LG/J mice would be an excellent model system for the study of gene‐by‐diet interaction in obesity.
Lipoprotein Oxidation and Plasma Vitamin E in Nondiabetic Normotensive Obese Patients
Authors: Myara Isaac , Alamowitch Catherine , Michel Odile , Heudes Didier , Bariety Jean , Guy‐Grand Bernard , Chevalier Jacques
Published: April 2008

Objective: To correlate the susceptibility of low‐(LDL) and very‐low‐density lipoprotein to oxidation in vitro and the concentrations of serum antibodies against malondialdehyde‐modified LDL and plasma vitamin E with the anthropometric and laboratory characteristics of obesity.

Research Methods and Procedures: A total of 75 nondiabetic, normotensive obese patients were assigned to one of four groups according to their body mass index (BMI): moderately obese (30 ≤ BMI ≤ 34.9 kg/m2, n = 11), severely obese (35 ≤ BMI ≤ 39.9 kg/m2, n = 20), morbidly obese (40 ≤ BMI ≤ 50 kg/m2, n = 29), and very severely obese (BMI > 50 kg/m2, n = 15).

Results: The oxidation lag time for LDL from patients with a BMI ≥35 kg/m2 was shorter than that for LDL from non‐obese controls (n = 13), whereas very‐low‐density lipoprotein oxidation lag times were not significantly different. The serum antibodies against modified LDL were similar in all groups, whereas the plasma vitamin E concentrations of obese patients were decreased (p ≤ 0.01). There was a negative correlation between LDL oxidation lag time and BMI (r = −0.35, p = 0.0008), and between plasma vitamin E and BMI (r = −0.53, p < 0.0001) and waist‐to‐hip ratio (r = −0.40, p = 0.0003).

Discussion: The LDL of nondiabetic, normotensive obese patients is more readily oxidized, and plasma vitamin E concentrations are low. These are both risk factors for coronary heart disease.
Evidence for Genetic Factors Underlying the Insulin Resistance Syndrome in American Indians
Authors: North Kari E. , Williams Ken , Williams Jeff T. , Best Lyle G. , Lee Elisa T. , Fabsitz Richard R. , Howard Barbara V. , Gray R. Stuart , MacCluer Jean W.
Published: April 2008

Previous analyses of American Indians of the Strong Heart Study have demonstrated that various insulin‐resistance variables cluster, although knowledge about the genetic determination of these clusters is unknown. In an effort to explore the influences on the aggregation of insulin‐resistance phenotypes, we used principal component factor analysis to examine the clustering of these phenotypes in participants of the Strong Heart Family Study and evaluated the genetic and environmental contributions of such factors. Nine traits were chosen for principal component factor analysis: BMI, diastolic blood pressure, fasting glucose, high‐density lipoprotein‐cholesterol, natural log‐transformed insulin, natural log‐transformed triglycerides, percentage of body fat, systolic blood pressure, and waist‐to‐hip ratio. Analyses revealed three clusters: glucose/insulin/obesity, blood pressure, and dyslipidemia factors. Using a variance component approach and accounting for the effects of age, sex, center, and medication, we detected significant heritabilities (h2) for the three factors: h2 = 0.67, h2 = 0.33, and h2 = 0.61, respectively. In multivariate analysis, no significant genetic correlations among factors were found. These results suggest that heredity explains a substantial proportion of the variability of the factors that underlie the insulin resistance syndrome in American Indians and that these factors are genetically independent.
Methods of Estimation of Visceral Fat: Advantages of Ultrasonography
Authors: Ribeiro‐Filho Fernando F. , Faria Alessandra N. , Azjen Sergio , Zanella Maria‐Teresa , Ferreira Sandra R.G.
Published: April 2008

Objective: To compare methods for the assessment of visceral fat with computed tomography (CT) and establish cutoffs to define visceral obesity based on such alternative methods.

Research Methods and Procedures: One hundred women (50.4 ± 7.7 years; BMI 39.2 ± 5.4 kg/m2) underwent anthropometric evaluation, bioelectrical impedance, DXA, abdominal ultrasonography (US), and CT scan.

Results: Waist circumference, waist‐to‐hip ratio (WHR), and US‐determined visceral fat values showed the best correlation coefficients with visceral fat determined by CT (r = 0.55, 0.54, and 0.71, respectively; p < 0.01). Fat mass determined by DXA was inversely correlated with visceral‐to‐subcutaneous‐fat ratio (r = −0.47, p < 0.01). Bioimpedance‐determined fat mass and skinfolds were correlated with only subcutaneous abdominal fat quantified by CT. Linear regression indicated US visceral‐fat distance and WHR as the main predictors of CT‐determined visceral fat (adjusted r2 = 0.51, p < 0.01). A waist measurement of 107 cm (82.7% specificity, 60.6% sensitivity) and WHR of 0.97 (78.8% specificity, 63.8% sensitivity) were chosen as discriminator values corresponding with visceral obesity diagnosed by CT. A value of 6.90 cm for visceral fat US‐determined diagnosed visceral obesity with a specificity of 82.8%, a sensitivity of 69.2%, and a diagnostic concordance of 74% with CT.

Discussion: US seemed to be the best alternative method for the assessment of intra‐abdominal fat in obese women. Its diagnostic value could be optimized by an anthropometric measurement. Prospective studies are needed to establish CT and US cutoffs for defining visceral‐fat levels related to elevated cardiovascular risk.
Insulin Resistance in Nondiabetic Morbidly Obese Patients: Effect of Bariatric Surgery
Authors: Pereira Juliano Alves , Lazarin Mary Aparecida C.T. , Pareja José Carlos , de Souza Aglécio , Muscelli Elza
Published: April 2008

Objective: To evaluate insulin action on substrate use and insulinemia in nondiabetic class III obese patients before and after weight loss induced by bariatric surgery.

Research Methods and Procedures: Thirteen obese patients (four men/nine women; BMI = 56.3 ± 2.7 kg/m2) and 13 lean subjects (five men/eight women; BMI = 22.4 ± 0.5 kg/m2) underwent euglycemic clamp, oral glucose tolerance test, and indirect calorimetry. The study was carried out before (Study I) and after (∼40% relative to initial body weight; Study II) weight loss induced by Roux‐en‐Y Gastric bypass with silastic ring surgery.

Results: The obese patients were insulin resistant (whole‐body glucose use = 19.7 ± 1.5 vs. 51.5 ± 2.4 μmol/min per kilogram fat‐free mass, p < 0.0001) and hyperinsulinemic in the fasting state (332 ± 86 vs. 85 ± 5 pM, p < 0.0001) and during the oral glucose tolerance test compared with the lean subjects. Fasting plasma insulin normalized after weight loss, whereas whole‐body glucose use increased (35.5 ± 3.7 μmol/min per kilogram fat‐free mass, p < 0.05 vs. Study I). The higher insulin clearance of obese did not change during the follow‐up period. Insulin‐induced glucose oxidation and nonoxidative glucose disposal were lower in the obese compared with the lean group (all p < 0.05). In Study II, the former increased slightly, whereas nonoxidative glucose disposal reached values similar to those of the control group. Fasting lipid oxidation was higher in the obese than in the control group and did not change significantly in Study II. The insulin effect on lipid oxidation was slightly improved (p = 0.01 vs. Study I).

Discussion: The rapid weight loss after surgery in obese class III patients normalized insulinemia and improved insulin sensitivity almost entirely due to glucose storage, whereas fasting lipid oxidation remained high.
Self‐Selected Macronutrient Diet Affects Energy and Glucose Metabolism in Brown Fat‐Ablated Mice
Authors: Ortmann Sylvia , Prinzler Julia , Klaus Susanne
Published: April 2008

Objective: Obese transgenic UCP‐DTA mice have largely ablated brown adipose tissue and develop obesity and diabetes, which are highly susceptible to a high‐fat diet. We investigated macronutrient self‐selection and its effect on development of obesity, diabetes, and energy homeostasis in UCP‐DTA mice.

Research Methods and Procedures: UCP‐DTA and wild‐type littermates were fed a semisynthetic macronutrient choice diet (CD) ad libitum from weaning until 17 weeks. Energy homeostasis was assessed by measurement of food intake, food digestibility, body composition, and energy expenditure. Diabetes was assessed by blood glucose measurements and insulin tolerance test.

Results: Wild‐type and UCP‐DTA mice showed a high fat preference and increased energy digestion on CD compared with a low‐fat standard diet. On CD, wild‐type mice accumulated less body fat (16.9%) than UCP‐DTA (32.6%) mice, although they had a higher overall energy intake. Compared with wild‐type mice, resting metabolic rate was reduced in UCP‐DTA mice irrespective of diet. UCP‐DTA mice progressively decreased their carbohydrate intake, resulting in an almost complete avoidance of carbohydrate. UCP‐DTA mice developed severe insulin resistance but showed decreased fed and fasted blood glucose on CD.

Discussion: In contrast to wild‐type mice, UCP‐DTA mice were not able to reduce their weight gain efficiency on CD. This suggests that, because of the high fat preference of the background strain and the increased metabolic efficiency, brown adipose tissue‐deficient mice still develop obesity and insulin resistance on a macronutrient CD even when decreasing overall energy intake. Through the avoidance of carbohydrates, however, they are able to maintain normoglycemia.
Stimulatory Effect of Leptin on Nitric Oxide Production Is Impaired in Dietary‐Induced Obesity
Authors: Bełtowski Jerzy , Wójcicka Grażyna , Jamroz Anna
Published: April 2008

Objective: We investigated the effect of leptin on nitric oxide production in lean and rats made obese by a high‐calorie diet.

Research Methods and Procedures: The animals were placed in metabolic cages, and urine was collected in 2‐hour periods after leptin (1 mg/kg intraperintoneally) or vehicle administration. Blood was obtained 0.5, 1, 2, 4, or 6 hours after injection.

Results: Leptin had no effect on systolic blood pressure in either lean or obese animals. Plasma concentration of NO metabolites (nitrites + nitrates, NOx) increased in lean rats by 31.5%, 58.0%, and 27.9% at 1, 2, and 4 hours after leptin injection, respectively. In the obese group, plasma NOx increased only at 2 hours (+36.5%). Leptin increased urinary NOx excretion by 31.8% in the first 2‐hour period after injection in lean but not in obese rats. In lean animals, leptin elevated plasma cyclic 3′, 5′‐guanosine monophosphate (cGMP) at 1, 2, and 4 hours by 35.3%, 96.3%, and 57.3%, respectively. In the obese group, plasma cGMP was higher only at 2 and 4 hours (+44.6% and +32.1%, respectively). Urinary excretion of cGMP increased in lean animals by 67.1% in the first period and by 50.4% in the second period. In the obese group, leptin induced a 53.9% increase in urinary cGMP excretion only in the first 2‐hour period.

Discussion: The stimulatory effect of leptin on NO production is impaired in dietary‐induced obesity; however, leptin does not increase blood pressure in obese animals, suggesting that other NO—independent depressor mechanisms are stimulated.
Vision and Eating Behavior in Obese Subjects
Authors: Barkeling Britta , Linné Yvonne , Melin Eva , Rooth Pål
Published: April 2008

Objective: Vision is one of a number of factors influencing the amount of food consumed during a meal. The purpose of this study was to investigate the impact of vision on the microstructure of the eating behavior of obese subjects.

Research Methods and Procedures: Eighteen obese subjects with a body mass index (mean ± SD) of 39.1 ± 6.3 kg/m2 twice consumed a standardized test meal in excess, once with and once without a blindfold. The microstructure of the eating behavior was registered by VIKTOR, a computerized eating monitor. Subjective motivation to eat (i.e., desire to eat, hunger, satiety, and prospective consumption) was rated by visual analogue scales (VASs) before, immediately after, and then hourly up to 3 hours after the test meals.

Results: The obese subjects ate 24% less food when blindfolded (359 ± 194 g vs. 472 ± 179 g; p < 0.01). Despite a smaller amount of food consumed when blindfolded, there were no significant differences with or without the blindfold for any of the VASs measuring subjective motivation to eat after test meals.

Discussion: The importance of vision in regulating our eating behavior was demonstrated in this study. The obese subjects ate 24% less food blindfolded without feeling less full. Eating blindfolded could be tested as a didactic tool to make obese subjects aware of what factors affect the termination of eating.
Objectively Measured Intensity of Physical Activity and Adiposity in Middle‐Aged Women
Authors: Tucker Larry A. , Peterson Travis R.
Published: April 2008

Objective: The aim of this study was to evaluate the relationship between objectively measured physical activity (ACT), particularly intensity of physical activity (iACT), and body fat percentage (BF%) in 278 middle‐aged women. Secondary purposes were to ascertain the association between physical activity duration (dACT) and BF% and the extent to which potentially confounding factors, including total ACT, energy intake, body weight, and season of assessment, influenced the relationship between iACT and BF%.

Research Methods and Procedures: A cross‐sectional design was used. Subjects were apparently healthy, 35 to 45 years old, premenopausal, nonsmokers, with BMIs < 30 kg/m2. Approximately 90 percent were white, 81% were married, and 37% were college graduates. ACT was assessed using Computer Science and Application accelerometers worn for 7 consecutive days. The accelerometers recorded movement continuously, and activity counts were collapsed into 10‐minute epochs. Intensity was indexed using seven activity count cut‐off points, and duration was based on the number of 10‐minute epochs at each intensity level. BF% was assessed using multiple measurements in the Bod Pod. Energy intake was measured using 7‐day weighed diet records during the same week subjects wore the accelerometers.

Results: BF% was strongly and inversely associated with iACT and dACT. Controlling for energy intake and body weight strengthened the relationships among iACT, dACT, and BF%. Control of total ACT weakened the association.

Discussion: Engaging in higher intensity and/or longer duration ACT is associated with lower BF% compared with lower intensity and/or shorter durations of activity.
Discrimination of Health Risk by Combined Body Mass Index and Waist Circumference
Authors: Ardern Christopher I. , Katzmarzyk Peter T. , Janssen Ian , Ross Robert
Published: April 2008

Objective: NIH Clinical Guidelines (1998) recommend the measurement of waist circumference (WC, centimeters) within body mass index (BMI, kilograms per square meter) categories as a screening tool for increased health risk.

Research Methods and Procedures: The Canada Heart Health Surveys (1986 through 1992) were used to describe the prevalence of the metabolic syndrome in Canada and to test the use of the NIH guidelines for predicting metabolic risk factors. The sample included 7981 participants ages 20 to 74 years who had complete data for WC, BMI, high‐density lipoprotein‐cholesterol, triglycerides, diabetic status, and systolic and diastolic blood pressures. National Cholesterol Education Program Adult Treatment Panel III risk categories were used to identify the metabolic syndrome and associated risk factors. Logistic regression was used to test the hypothesis that WC improves the prediction of the metabolic syndrome, within overweight (25 to 29.9 kg/m2) and obese I (30 to 34.9 kg/m2) BMI categories.

Results: The prevalence of the metabolic syndrome was 17.0% in men and 13.2% in women. The odds ratios (OR) for the prediction of the metabolic syndrome were elevated in overweight [OR, 1.85; 95% confidence interval (95%CI), 1.02 to 3.35] and obese (OR, 2.35; 95%CI, 1.25 to 4.42) women with a high WC compared with overweight and obese women with a low WC, respectively. On the other hand, WC was not predictive of the metabolic syndrome or component risk factors in men, within BMI categories.

Discussion: In women already at increased health risk because of an elevated BMI, the additional measurement of WC may help identify cardiovascular risk.
Fat Compartments and Apolipoprotein B‐100 Kinetics in Overweight‐Obese Men
Authors: Watts Gerald F. , Chan Dick C. , Barrett P. Hugh R. , Susekov Andrei V. , Hua Jianmin , Song Swithin
Published: April 2008

Objective: To examine the association between the kinetics of very‐low‐density‐lipoprotein (VLDL)‐apolipoprotein B‐100 (apoB) and intraperitoneal, retroperitoneal, subcutaneous abdominal, and total adipose tissue masses (IPATM, RPATM, SAATM, and TATM, respectively) in overweight/obese men.

Research Methods and Procedures: Hepatic secretion of VLDL was measured using an intravenous infusion of 1‐[13C]‐leucine in 51 men with a wide range of body mass index (25.1 to 42.2 kg/m2). Isotopic enrichment of VLDL‐apoB was measured using gas chromatography‐mass spectrometry and a multicompartmental model used to estimate VLDL‐apoB metabolic parameters. IPATM, RPATM, and SAATM (kilograms) were quantified between T11 and S1 using magnetic resonance imaging; TATM (kilograms) was determined using bioelectrical impedance. Insulin resistance was estimated by homeostasis model assessment (HOMA) score.

Results: In stepwise regression, IPATM was the best predictor of hepatic secretion of VLDL‐apoB (r = 0.390, p < 0.005) and TATM was the best predictor of VLDL‐apoB fractional catabolic rate (r = 0.282, p < 0.05). IPATM remained significantly associated with VLDL‐apoB secretion after adjusting for TATM or HOMA score (r = 0.360, p < 0.01 and r = 0.310, p < 0.05, respectively). This association was also independent of age, dietary intake, and body mass index. None of the fat compartments were significantly associated with the fractional catabolic rate of VLDL‐apoB after adjusting for HOMA score.

Discussion: In overweight/obese men, the quantity of both IPATM and TATM determine the kinetics of VLDL‐apoB. The effect of IPATM on VLDL‐apoB secretion is independent of both total fat mass and the degree of insulin resistance.
Adipose Tissue Quantification by Imaging Methods: A Proposed Classification
Authors: Shen Wei , Wang ZiMian , Punyanita Mark , Lei Jianbo , Sinav Ahmet , Kral John G. , Imielinska Celina , Ross Robert , Heymsfield Steven B.
Published: April 2008

Recent advances in imaging techniques and understanding of differences in the molecular biology of adipose tissue has rendered classical anatomy obsolete, requiring a new classification of the topography of adipose tissue. Adipose tissue is one of the largest body compartments, yet a classification that defines specific adipose tissue depots based on their anatomic location and related functions is lacking. The absence of an accepted taxonomy poses problems for investigators studying adipose tissue topography and its functional correlates. The aim of this review was to critically examine the literature on imaging of whole body and regional adipose tissue and to create the first systematic classification of adipose tissue topography. Adipose tissue terminology was examined in over 100 original publications. Our analysis revealed inconsistencies in the use of specific definitions, especially for the compartment termed “visceral” adipose tissue. This analysis leads us to propose an updated classification of total body and regional adipose tissue, providing a well‐defined basis for correlating imaging studies of specific adipose tissue depots with molecular processes.
Obesity and Quality of Life: Mediating Effects of Pain and Comorbidities
Authors: Heo Moonseong , Allison David B. , Faith Myles S. , Zhu Shankuan , Fontaine Kevin R.
Published: April 2008

Objective: To estimate the association between body mass index (BMI) and health‐related quality of life (HRQL) and examine whether joint pain and obesity‐related comorbidities mediate the BMI‐HRQL association.

Research Methods and Procedures: Population‐based survey data from the 1999 Behavioral Risk Factor Surveillance Survey. Adults (N = 155, 989) were classified according to BMI as underweight (<18.5 kg/m2), desirable weight (18.5 to 24.9 kg/m2), overweight (25 to 29.9 kg/m2), obese class I (30 to 34.9 kg/m2), obese class II (35 to 39.9 kg/m2), and obese class III (≥40 kg/m2). Data including general health status, unhealthy days in the past 30 caused by physical problems and mental problems, and total unhealthy days in the past 30 were collected.

Results: After adjusting for age, sex, race, smoking, education, and income, we observed J‐shaped associations between BMI and HRQL. Compared with desirable weight adults, underweight, overweight, and obesity classes I, II, and III adults [odds ratio (OR) = 1.57, 1.19, 1.95, 2.72, and 4.36, respectively] were significantly (p < 0.001) more likely to report fair/poor general health status. For unhealthy days caused by physical problems, the corresponding ORs were 1.51, 1.15, 1.66, 2.27, and 3.61 (p < 0.001). For unhealthy days caused by mental problems, the ORs were 1.35, 1.14 1.43, 1.57, and 2.25 (p < 0.001). For total unhealthy days, the corresponding ORs were 1.27, 1.09, 1.37, 1.73, and 2.46 (p < 0.01). Adding joint pain and obesity‐related comorbidities into models attenuated BMI‐HRQL associations.

Discussion: Associations between BMI and HRQL indices were J‐shaped. Joint pain and comorbidities may mediate BMI‐HRQL associations.
Volume Estimates by Imaging Methods: Model Comparisons with Visible Woman as the Reference
Authors: Shen Wei , Wang ZiMian , Tang Haiying , Heshka Stanley , Punyanitya Mark , Zhu Shankuan , Lei Jianbo , Heymsfield Steven B.
Published: April 2008

Objective: To compare the accuracy of four volume estimation models to actual tissue and organ volumes measured in the visible woman.

Methods: Actual volumes were calculated from 1‐mm‐thick visible woman images that were segmented for five major components including subcutaneous and visceral adipose tissue across the 1730 available slices. Four available models resolved to two equations: truncated cone/truncated pyramid vs. two‐column/parallel trapezium. Between‐slice interval and initial slice were systematically varied when deriving component volumes using the two equations in four regions.

Results: For each compartment and each between‐slice interval, the means of the two‐column model were always the same as the corresponding reference volumes, whereas those of the truncated cone model were smaller than the reference volumes. Similarly, the coefficient variation for the two‐column model was always smaller than for the truncated cone model.

Discussion: The equation based on the parallel trapezium and the two‐column models is more accurate in estimating tissue volumes than the corresponding equation for truncated pyramid and truncated cone models. This finding has important implications for the volume calculations of imaging‐based body compartments such as adipose tissue.
Insulin‐ and Exercise‐Stimulated Skeletal Muscle Blood Flow and Glucose Uptake in Obese Men
Authors: Hällsten Kirsti , Yki‐Järvinen Hannele , Peltoniemi Pauliina , Oikonen Vesa , Takala Teemu , Kemppainen Jukka , Laine Hanna , Bergman Jörgen , Bolli Geremia B. , Knuuti Juhani , Nuutila Pirjo
Published: April 2008

Objective: Insulin resistance in obese subjects results in the impaired use of glucose by insulin‐sensitive tissues, e.g., skeletal muscle. In the present study, we determined whether insulin resistance in obesity is associated with an impaired ability of exercise to stimulate muscle blood flow, oxygen delivery, or glucose uptake.

Research Methods and Procedures: Nine obese (body mass index = 36 ± 2 kg/m2) and 11 age‐matched nonobese men (body mass index = 22 ± 1 kg/m2) performed one‐legged isometric exercise during hyperinsulinemia. Rates of femoral muscle blood flow, oxygen consumption, and glucose uptake were measured simultaneously in both legs using [15O]H2O, [15O]O2, [18F]fluoro‐deoxy‐glucose, and positron emission tomography.

Results: The obese subjects exhibited resistance to insulin stimulation of glucose uptake in resting muscle, regardless of whether glucose uptake was expressed per kilogram of femoral muscle mass (p = 0.001) or per the total mass of quadriceps femoris muscle. At similar workloads, oxygen consumption, blood flow, and glucose uptake were lower in the obese than the nonobese subjects when expressed per kilogram of muscle, but similar when expressed per quadriceps femoris muscle mass.

Discussion: We conclude that obesity is characterized by insulin resistance of glucose uptake in resting skeletal muscle regardless of how glucose uptake is expressed. When compared with nonobese individuals at similar absolute workloads and under identical hyperinsulinemic conditions, the ability of exercise to increase muscle oxygen uptake, blood flow, and glucose uptake per muscle mass is blunted in obese insulin‐resistant subjects. However, these defects are compensated for by an increase in muscle mass.
A Genome‐Wide Scan for Body Mass Index among Nigerian Families
Authors: Adeyemo Adebowale , Luke Amy , Cooper Richard , Wu Xiaodong , Tayo Bamidele , Zhu Xiaofeng , Rotimi Charles , Bouzekri Nourdine , Ward Ryk
Published: April 2008

Objective: Interest in mapping genetic variants that are associated with obesity remains high because of the increasing prevalence of obesity and its complications worldwide. Data on genetic determinants of obesity in African populations are rare.

Research Methods and Procedures: We have undertaken a genome‐wide scan for body mass index (BMI) in 182 Nigerian families that included 769 individuals.

Results: The prevalence of obesity was only 5%, yet polygenic heritability for BMI was in the expected range (0.46 ± 0.07). Tandem repeat markers (402) were typed across the genome with an average map density of 9 cM. Pedigree‐based analysis using a variance components linkage model demonstrated evidence for linkage on chromosome 7 (near marker D7S817 at 7p14) with a logarithm of odds (LOD) score of 3.8 and on chromosome 11 (marker D11S2000 at 11q22) with an LOD score of 3.3. Weaker evidence for linkage was found on chromosomes 1 (1q21, LOD = 2.2) and 8 (8p22, LOD = 2.3). Several candidate genes, including neuropeptide Y, DRD2, APOA4, lamin A/C, and lipoprotein lipase, lie in or close to the chromosomal regions where strong linkage signals were found.

Discussion: The findings of this study suggest that, as in other populations with higher prevalences of obesity, positive linkage signals can be found on genome scans for obesity‐related traits. Follow‐up studies may be warranted to investigate these linkages, especially the one on chromosome 11, which has been reported in a population at the opposite end of the BMI distribution.
Epicardial Fat from Echocardiography: A New Method for Visceral Adipose Tissue Prediction
Authors: Iacobellis Gianluca , Assael Filippo , Ribaudo Maria Cristina , Zappaterreno Alessandra , Alessi Giuseppe , Di Mario Umberto , Leonetti Frida
Published: April 2008

Objective: To validate transthoracic echocardiography as an easy and reliable imaging method for visceral adipose tissue (VAT) prediction. VAT is recognized as an important indicator of high cardiovascular and metabolic risk. Several methods are applied to estimate VAT, with different results.

Research Methods and Procedures: We selected 60 healthy subjects (29 women, 31 men, 49.5 ± 16.2 years) with a wide range of body mass indexes. Each subject underwent transthoracic echocardiogram and magnetic resonance imaging (MRI) to measure epicardial fat thickness on the right ventricle. Measurements of epicardial adipose tissue thickness were obtained from the same echocardiographic and MRI views and points. MRI was also used to measure VAT cross‐sectional areas at the level of L4 to L5. Anthropometric indexes were also measured.

Results: Subjects with predominant visceral fat accumulation showed higher epicardial adipose tissue thickness than subjects with predominant peripheral fat distribution: 9.97 ± 2.88 vs. 4.34 ± 1.98 (p = 0.005) and 7.19 ± 2.74 vs. 3.43 ± 1.64 (p = 0.004) in men and women, respectively. Simple linear regression analysis showed an excellent correlation between epicardial adipose tissue and waist circumference (r = 0.895, p = 0.01) and MRI abdominal VAT (r = 0.864, p = 0.01). Multiple regression analysis showed that epicardial adipose tissue thickness (r2 = 0.442, p = 0.02) was the strongest independent variable correlated to MRI VAT. Bland test confirmed the good agreement between the two methods.

Discussion: Epicardial adipose tissue showed a strong correlation with anthropometric and imaging measurements of VAT. Hence, transthoracic echocardiography could be an easy and reliable imaging method for VAT prediction.
Relationship of Serum Adiponectin and Leptin Concentrations with Body Fat Distribution in Humans
Authors: Staiger Harald , Tschritter Otto , Machann Jürgen , Thamer Claus , Fritsche Andreas , Maerker Elke , Schick Fritz , Häring Hans‐Ulrich , Stumvoll Michael
Published: April 2008

Objective: We investigated whether serum concentrations of adiponectin are determined by body fat distribution and compared the findings with leptin.

Research Methods and Procedures: Serum concentrations of adiponectin and leptin were measured by radioimmunoassay (n = 394) and analyzed for correlation with sex, age, and body fat distribution, i.e., waist‐to‐hip ratio, waist and hip circumference, and subcutaneous adipose tissue area of the lower leg as assessed by magnetic resonance imaging.

Results: After adjusting for sex and percentage of body fat, adiponectin was negatively (r = −0.17, p < 0.001) and leptin was positively (r = 0.22, p < 0.001) correlated with waist‐to‐hip ratio. Leptin, but not adiponectin, correlated with both waist (r = 0.49, p < 0.001) and hip circumference (r = 0.46, p < 0.001). Furthermore, leptin, but not adiponectin, correlated with the proportion of subcutaneous fat of the lower leg cross‐sectional area (r = 0.37, p < 0.001).

Discussion: These data suggest that both adipocytokines are associated with central body fat distribution, and serum adiponectin concentrations are determined predominantly by the visceral fat compartment.
Genetic Variation in the Leptin Receptor Gene, Leptin, and Weight Gain in Young Dutch Adults
Authors: van Rossum Caroline T.M. , Hoebee Barbara , van Baak Marleen A. , Mars Monica , Saris Wim H.M. , Seidell Jacob C.
Published: April 2008

Objective: To investigate the association between leptin levels, polymorphisms in the leptin receptor (LEPR) gene, and weight gain.

Research Methods and Procedures: From two large prospective cohorts in The Netherlands (n = 17, 500), we compared the baseline leptin of 259 subjects who had gained an average of 12.6 kg (range 5.5 to 33 kg) with 277 subjects who kept stable weight (range −2.6 to 3.1 kg) after a mean follow‐up of 6.8 years. Three polymorphisms in the LEPR gene (Lys109Arg, Gln223Arg, and Lys656Asn) were determined.

Results: Weight gainers had significantly higher baseline leptin levels than those who kept stable weight (odds ratio = 1.27, 95% confidence interval 1.1 to 1.5, per SD increase in loge‐transformed leptin). Weight gainers with the Arg109 or the Arg223 alleles had higher leptin levels compared with the noncarriers of these alleles. Only among men, the association between leptin and weight gain tended to be stronger among those with an Arg223 allele compared with those without this mutation.

Discussion: Relatively high leptin levels predict weight gain, suggesting that leptin resistance plays a role in the development of obesity in the general population. Higher leptin levels for those with a Lys109Arg or Gln223Arg mutation (or a linked other marker) may imply that these subjects have a modified functional leptin receptor. However, the role of these mutations on weight gain is limited.
High Dietary Calcium Reduces Body Fat Content, Digestibility of Fat, and Serum Vitamin D in Rats
Authors: Papakonstantinou Emilia , Flatt William P. , Huth Peter J. , Harris Ruth B.S.
Published: April 2008

Objective: This study investigated which aspect of energy balance was responsible for the decrease in body fat content of rats fed a high‐calcium, high—dairy protein diet.

Research Methods and Procedures: Male Wistar rats were fed a control diet (25% kcal fat, 14% kcal protein from casein, 0.4% by weight calcium) or high‐calcium diet (25% kcal fat, 7% kcal protein from nonfat dry milk, 7% kcal protein from casein, 2.4% calcium) for 85 days. Body weights, digestible energy intakes, energy expenditures, rectal temperatures, body composition, and serum glucose, insulin, free fatty acids, triglycerides, and 1, 25‐dihydroxyvitamin D were measured.

Results: Rats fed high‐calcium diet gained significantly less weight than controls and had 29% less carcass fat. Gross energy intake was not significantly different between groups, but digestible energy was 90% of gross energy in the high‐calcium diet compared with 94% in the control diet because of increased fecal excretion of dietary lipid. The difference in digestible energy intake accounted for differences in carcass energy. Body temperatures and energy expenditures of the rats were not different. The high‐calcium diet reduced serum triglycerides by 23% and serum 1, 25‐dihydroxyvitamin D by 86%.

Discussion: These results confirm that a high‐calcium diet decreases body weight and fat content due to a lower digestible energy intake caused by increased fecal lipid and a nonsignificant reduction in gross energy intake.
Phenylethanolamine N‐Methyltransferase G‐148A Genetic Variant and Weight Loss in Obese Women
Authors: Peters Warren R. , MacMurry James P. , Walker Jennifer , Giese Russell J. , Comings David E.
Published: April 2008

Objective: To understand the impact of the phenylethanolamine N‐methyltransferase (PNMT) G‐148A gene and nutritional variables on weight loss in obese women.

Research Methods and Procedures: One hundred forty‐nine women, ages 45 to 65 with a body mass index of >30 kg/m2, participated in a 6‐month, open‐label intervention that included sibutramine (15 mg/d) and a monthly health‐education class. Anthropometric measurements, vital signs, food frequency, exercise log, medication compliance, and psychological and sociological questionnaires were completed each month. Genetic polymorphisms of PNMT were determined.

Results: Univariate analysis of G/G, G/A, and A/A genotypes against tertiles of percentage of weight loss were significant at 3 but not at 6 months (Pearson χ2: p < 0.006; homozygous/heterozygosity: p < 0.002, p < 0.253, and p < 0.122, respectively). A regression model that included the PNMT genetic variation and certain nutrition and exercise variables demonstrated that only the PNMT gene (β = 0.360, SE 0.585, and p = 0.003) was statistically significant at 6 months, and the total calories (β = −0.925, SE = 0.004, and p = 0.009), fiber intake (β = 0.621, SE = 0.124, and p = 0.000), and PNMT (β = 0.262, SE = 1.415, and p = 0.024) were significant.

Discussion: The homozygosity/heterozygosity of the PNMT gene was highly predictive of significant weight loss with sibutramine during the first 3 months, which highlights the need for specific pharmacotherapy. The early weight‐loss success of those subjects who were homozygous for PNMT may have motivated and selected those that would make further dietary changes, which then augmented their final weight loss.
Objectively Measured Physical Activity in a Representative Sample of 3‐ to 4‐Year‐Old Children
Authors: Jackson Diane M. , Reilly John J. , Kelly Louise A. , Montgomery Colette , Grant Stan , Paton James Y.
Published: April 2008

Objective: This study aimed to describe levels of physical activity in a representative sample of preschool children and to quantify tracking of activity over 1 year.

Research Methods and Procedures: Physical activity (mean accelerometry counts/minute) was assessed over 3 days using the Computer Science and Applications accelerometer in 3‐ to 4‐year‐old children (n = 104; 52 boys; mean age, 3.7 ± 0.4 years). In 60 children (30 boys), measurements were repeated 1 year later.

Results: Mean total activity at baseline was 777 ± 207 counts/minute in boys and 657 ± 172 counts/minute for girls; this gender difference was significant (p < 0.001). In the cross‐sectional analysis, total activity was significantly positively related to age (r = 0.37, p = 0.007). In the sample followed up for 1 year, mean total activity was 849 ± 252. The longitudinal analysis confirmed that total physical activity increased over the 1‐year period (paired Student's t test, p < 0.001). The tracking rank order correlation coefficient of total activity count over 1 year was r = 0.40 (p < 0.001).

Discussion: This study suggests that total activity increases during the preschool period in Scottish children and that gender differences in total activity are present early in life. Tracking of total activity was only modest, but adequate assessment of tracking requires methodological research aimed at elucidating the biological meaning of accelerometer output.