Search

Background/Objectives:We evaluated the agreement of air displacement plethysmography (ADP) and bioelectrical impedance analysis (BIA) with dual-energy X-ray absorptiometry (DXA) for the assessment of percent fat mass (%FM) in morbidly obese women.Subjects/Methods:Fifty-seven women aged 19-55 years and with a body mass index (BMI) ranging from 37.3 to 55.2 kg/m2 were studied. Values of %FM were obtained directly from ADP and DXA, whereas for BIA we estimated fat-free mass (FFM) from an equation for morbidly obese subjects and calculated %FM as (weight−FFM)/weight.Results:The mean (s.d.) difference between ADP and DXA for the assessment of %FM was −2.4% (3.3%) with limits of agreement (LOA) from −8.8% to 4.1%. The mean (s.d.) difference between BIA and DXA for the assessment of %FM was 1.7% (3.3%) with LOA from −4.9% to 8.2%.Conclusion:ADP-DXA and BIA-DXA are not interchangeable methods for the assessment of body composition in morbidly obese women. [ABSTRACT FROM AUTHOR]

Objective:To evaluate predictors of non-alcoholic fatty liver disease (NAFLD) in obese children.Design:Cross-sectional study.Subjects:Two hundred and sixty-eight obese children not consuming alcohol and without hepatitis B or C were consecutively studied at an auxology clinic.Measurements:Alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl-transferase (GGT), cholesterol, high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol, triglycerides, uric acid, glucose, glucose during oral glucose tolerance testing (OGTT), insulin, insulin during OGTT, insulin resistance as estimated by homeostasis model assessment (HOMA), C-reactive protein (CRP), and systolic and diastolic blood pressure were measured. Fatty liver was diagnosed by ultrasonography using standard criteria. Univariable and multivariable logistic regression was used to evaluate predictors of NAFLD. All predictors except gender and pubertal status were modeled as continuous variables.Results:NAFLD was detected in 44% of obese children. At univariable analysis, male gender, Z-score of body mass index (BMI) (Z-BMI), ALT, AST, GGT, triglycerides, uric acid, glucose, glucose during OGTT, insulin, insulin during OGTT, HOMA, CRP and systolic blood pressure were predictors of NAFLD, whereas HDL-cholesterol and late-pubertal status were predictors of the normal liver. At multivariable analysis, however, only Z-BMI, ALT, uric acid, glucose during OGTT and insulin during OGTT were independent predictors of NAFLD.Conclusion:Z-BMI, ALT, uric acid, glucose during OGTT and insulin during OGTT are independent predictors of NAFLD in Italian obese children, with most of the prediction explained by ALT and Z-BMI.Sponsorship:Centro Studi Fegato and Progetti di Ricerca Corrente, Istituto Auxologico Italiano.European Journal of Clinical Nutrition (2007) 61, 877–883; doi:10.1038/sj.ejcn.1602588; published online 6 December 2006 [ABSTRACT FROM AUTHOR]

BACKGROUND:Motor capabilities are reduced in obese (OB) individuals, and this impairment may result also from quantitative variation of muscle mass due to alterations in body composition.OBJECTIVE:This study aims to evaluate the differences in body mass (BM) and composition, as well as in muscle strength (ST) and power output (\[Wdot]) between OB and NW males and females, and to test the hypothesis that variations in body composition affect muscle performance in OB subjects.DESIGN AND METHODS:Body composition (determined by BIA with a two-compartment model), upper and lower limb maximum ST (evaluated with isotonic machines) and lower limb maximum anaerobic \[Wdot] (measured with a jumping test) were studied in a group of 95 extremely OB subjects (OB: 28 males, 67 females; mean age±s.d.: 29.3±7.0 y; BMI: 41.2±4.4 kg/m2) and in a control group of 18 NW voluntary subjects (NW: eight males, 10 females; age: 30.3±5.3 y; BMI: 22.6±2.1 kg/m2).RESULTS:OB male and female subjects differed significantly with increases in BM being attained by a similar contribution of fat mass (FM) and fat-free mass (FFM) in male subjects, but mainly contributed by FM in female subjects. Compared with NW, both OB men and women had a greater amount of FFM (P<0.001) and, since a general linear correlation was found between ST and FFM (ST (N)=64.4 FFM (kg)−190.0, R2=0.612, P<0.001), they developed higher values of ST (P<0.05) than their respective NW counterparts. For the same reason, both OB and NW male subjects had higher ST (P<0.001) than their female counterparts. Correction for FFM eliminated all gender- and obesity-related ST differences. On the contrary, in spite of their higher absolute muscle strength, both OB men and women could develop absolute \[Wdot] similar to that of NW subjects, and were notably less powerful per unit BM than NW subjects (P<0.001), women being most affected among the OB.CONCLUSIONS:Obesity-related variation in body composition differs considerably by gender, and is responsible for differences in muscle performance: the higher muscle strength observed in OB subjects (both men and women) and in male subjects (both OB and NW) is accounted for by a greater amount of FFM. Nonetheless, biomechanical limitations appear to impair muscle power development during jumping in OB individuals.International Journal of Obesity (2005) 29, 833–841. doi:10.1038/sj.ijo.0802955 Published online 26 April 2005 [ABSTRACT FROM AUTHOR]

OBJECTIVE:: To investigate the short- and medium-term (ie, at 1-y follow-up) effects of a hospital-based body weight reduction (BWR) program lasting 3 weeks in severely obese individuals. DESIGN:: Longitudinal, clinical intervention study entailing energy-restricted diet, tailored aerobic-strength exercise, psychological counselling and nutritional education during a 3-week period followed by 49 weeks of indirect supervision at home. SUBJECTS:: In all, 45 women and 19 men aged 30.2±7.2?y (mean±s.d.) with severe obesity (BMI: 41.3±4.3?kg/m2), classified as weight losers (final

OBJECTIVE:: To measure body water distribution and to evaluate the accuracy of eight-polar bioelectrical impedance analysis (BIA) for the assessment of total body water (TBW) and extracellular water (ECW) in severe obesity. DESIGN:: Cross-sectional study. SETTING:: Obesity clinic. SUBJECTS:: In all, 75 women aged 18-66?y, 25 with body mass index (BMI) between 19.1 and 29.9?kg/m2 (ie not obese), 25 with BMI between 30.0 and 39.9?kg/m2 (ie class I and II obese), and 25 with BMI between 40.0 and 48.2?kg/m2 (ie class III obese). METHODS:: TBW and ECW were measured by2H2O and Br dilution. Body resistance (R) was obtained by summing the resistances of arms, trunk and legs as measured by eight-polar BIA (InBody 3.0, Biospace, Seoul, Korea). The resistance index at a frequency of x kHz (RIx) was calculated as height2/Rx. RESULTS:: ECW?:?TBW was similar in women with class III (46±3%, mean±s.d.) and class I-II obesity (45±3%) but higher than in nonobese women (39±3%, P<0.05). In a random subsample of 37 subjects, RI500 explained 82%of TBW variance (P<0.0001) and cross-validation of the obtained algorithm in the remaining 38 subjects gave a percent root mean square error (RMSE%) of 5%and a pure error (PE) of 2.1?l. In the same subjects, RI5 explained 87%of ECW variance (P<0.0001) and cross-validation of the obtained algorithm gave a RMSE%of 8%and a PE of 1.4?l. The contribution of weight and BMI to the prediction of TBW and ECW was nil or negligible on practical grounds. CONCLUSIONS:: ECW?:?TBW is similar in women with class I-II and class III obesity up to BMI values of 48.2?kg/m2. Eight-polar BIA offers accurate estimates of TBW and ECW in women with a wide range of BMI (19.1-48.2?kg/m2) without the need of population-specific formulae. SPONSORSHIP:: Progetti di Ricerca Corrente, Istituto Auxologico Italiano.European Journal of Clinical Nutrition (2005) 59, 155-160. doi:10.1038/sj.ejcn.1602049 Published online 1 September 2004 [ABSTRACT FROM AUTHOR]