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Fat distribution changes during the freshman year of college in females: A pear or an apple?
H.R. Hull, K.C. Heesch, M.L. Morrow, M.K. Dinger and D.A. Fields
Reliability of percent body fat estimates determined via multicompartment models
J. LaForgia, S. M. Gunn, R. T. Withers and F. Leaney
Usefulness of the waist-to-height ratio to predict trunk fat accumulation in young Japanese and Australian Caucasian males living in Australia
M. Kagawa, A.P. Hills and C.W. Binns
Body composition of HIV-infected adults in Ethiopia : validation of bioelectrical impedance analysis
H. Fufa, M. Umeta, G. Akalu, S. Taffesse, L. Ketema, T. Messele, C. Slater, D. Zerfu, M. Kassa and H. Aguenaou
Modelling the relationship between body fat and the BMI
T.C. Mills1, D. Gallagher2, J. Wang2 and S. Heshka2
International Journal of Body Composition Research 2007 Vol. 5 No. 2: 45-50
H.R. Hull1,2, K.C. Heesch3, M.L. Morrow2, M.K. Dinger1 and D.A. Fields2,4
1Department of Health and Exercise Science, University of Oklahoma, Norman, OK, USA; 2Department of Pediatrics, University of Oklahoma Health Science Center, Oklahoma City, OK, USA; 3School of Human Movement Studies, Brisbane, Australia; 4Children's Medical Research Institute's Metabolic Research Center, Oklahoma City, OK, USA.
Objective. One in five college students are classified as overweight and exhibit poor physical activity and dietary behaviors. The purpose of this study was to track changes in upper and lower body fat and fat-free mass in college freshmen female students. A secondary purpose was to understand changes in body composition in those who made a conscious effort to lose weight and those who made no effort to lose weight during their freshmen year of college.
Methods. Total and regional fat and fat-free mass were assessed during the freshman year of college (ie 2004 fall semester and 2005 spring semester) using dual-energy X-ray absorptiometry (DXA).
Results: One-hundred thirty-seven females completed both visits (18.2 ± 0.7 yr; 58.6 ± 8.2 kg; 21.9 ± 3 kg/m2) and had significant (P<0.001) increases in body weight, total fat and fat-free mass and in regional arm, leg, and trunk fat mass and with significant (P<0.05) increases also observed in arm and trunk fat-free mass. For both those making a conscious effort and making no effort to lose weight, significant (P<0.05) increases in body weight, body mass index and fat-free mass were observed. Only those participants making no effort gained a significant (P=0.0001) amount of total fat mass. Both groups increased significantly (P=0.05) in both arm and trunk fat and fat-free mass.
Conclusion. Of the 1.1 kg weight increase observed 54% was deposited as trunk fat mass. Regardless of whether females attempted to lose weight or not, similar and significant increases in weight and regional body fat changes were found with both groups depositing 58% and 52%, respectively, of their total weight gain as fat in the trunk region. Though preliminary, results suggest that freshmen females preferentially deposit fat in the trunk region.
Key words: body composition, regional fat, female fat patterning
International Journal of Body Composition Research 2007 Vol. 5 No. 2: 51-56
J. LaForgia1, S. M. Gunn2, R. T. Withers2 and F. Leaney3
1School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia; 2Exercise Physiology Laboratory, School of Education, Flinders University, Adelaide, South Australia; 3CSIRO (Australia), Land and Water, Glen Osmond, South Australia, Australia.
Objective. The 3-compartment (fat mass: FM, total body water: TBW, and fat-free dry solid) and 4-compartment
(FM, TBW, bone-mineral mass: BMM, and residual) body composition models require multiple measurements
and therefore suffer from propagation of measurement error. This study investigated if propagated error significantly
undermines the superiority of multi-compartment models by determining their reliability and precision. Design. A heterogeneous group of five men (50.6 ± 22.4 yr, 70.1 ± 4.9 kg, 21.6 ± 6.3 % body fat or %BF) and six women (29.4 ± 13.2 yr, 64.1 ± 10.9 kg, 27.2 ± 8.0 %BF) were measured for body density (BD), TBW and BMM twice within a 24 h period via underwater weighing, deuterium dilution and dual-energy X-ray absorptiometry, respectively.
Results. The %BF data for both models yielded intraclass-correlation coefficients of 0.993. Both models displayed very similar technical errors of measurement (TEM = ~0.6 %BF, TEM% = ~2.5). These values are less than a previously reported TEM value (~ 1.1 %BF) for multi-compartment models. The improved precision of our work could be associated with the greater accuracy of deuterium measures via isotope ratio mass spectrometry compared with the infrared spectrophotometry used by the previous investigators. Notwithstanding, the determination of TBW contributed a larger error (0.8%BF) to the multi-compartment models compared with the measurement of BD (0.05% BF).
Conclusion. The superior accuracy of multi-compartment models compared with the popular 2-compartment hydrometry and hydrodensitometry methods is not offset by measurement errors.
Key words: body composition, precision, DXA, body density, total body water
International Journal of Body Composition Research 2007 Vol. 5 No. 2: 57-63
M. Kagawa1,2,3, A.P. Hills1,2 and C.W. Binns3
1ATN Centre for Metabolic Fitness, School of Human Movement Studies, Queensland University of Technology, Brisbane, Qld, Australia; 2Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Qld, Australia; 3School of Public Health, Curtin University of Technology, Perth, Qld, Australia.
Objective. To determine the usefulness of the waist-to-height ratio (WHtR) to estimate trunk-fat deposition in a multi-ethnic population of Japanese and Australian Caucasian adult males (18-40 years of age) living in Australia.
Design. Body composition of 45 Japanese and 42 Australian Caucasian males was measured using dualenergy X-ray absorptiometry (DXA) and relationships between the body composition results and anthropometric indices, including WHtR, body-mass index (BMI), waist circumference (WC) and sum of skinfolds (SSF) were determined.
Results. WHtR was well correlated (r ranged from 0.527 to 0.697 in Japanese, 0.496 to 0.576 in Australians) with trunk fat and percentage body fat (%BF) and less correlated with trunk lean mass compared to BMI and WC (ie, fat-sensitive). Compared to other anthropometric parameters, WHtR was the only index which estimation of both %BF and percentage body fat in the trunk region (%TF) were not affected by ethnicity and age. The study also found that the relationship between WHtR and proportion of trunk fat relative to the total body fat (P(trunk)) was influenced by age and ethnicity. The influence of ethnicity may be associated with a significant (P<0.01) difference in body proportions between Japanese and Australian Caucasian males.
Conclusion. Although further validation is recommended, findings from the current study suggest that WHtR may be useful as an alternative option to identify individuals with excessive trunk-fat deposition and at risk of the metabolic syndrome in a multi-ethnic population.
Key words: waist-to-height ratio, body composition, DXA, Japanese, Australian, Caucasian, males, percentage body fat, body proportion
International Journal of Body Composition Research 2007 Vol. 5 No. 2 65 -71
H. Fufa1, M. Umeta1, G. Akalu1, S. Taffesse1 , L. Ketema1, T. Messele1, C. Slater2, D. Zerfu 1, M. Kassa3 and H. Aguenaou3
1Ethiopian Health and Nutrition Research Institute (EHNRI), Addis Ababa , Ethiopia ; 2Cumbria, UK ; 3Laboratoire de Nutrition Alimentation, Universite Ibn Tofail, Kenitra , Morocco .
Background. Accurate methods of measuring body composition are important for nutritional assessment of HIV-infected individuals, particularly in developing nations. In HIV-infected individuals, it is important to know whether changes in body weight are due to changes in body fatness or in fat-free mass. Bioelectrical impedance analysis (BIA) is a non-invasive method of estimating body composition. However, equations for predicting body composition from impedance are population-specific.
Objective. The present study set out to develop and validate BIA prediction equations for measuring body composition in Ethiopian adults living with HIV/AIDS using deuterium dilution as the criterion method.
Design. Impedance was measured using BIA at 50 kHz and deuterium dilution was used as the criterion method. TBW was measured in 138 adults (31 males and 107 females) with HIV. The study group was randomly divided into model (n=73 females and 19 males) and validation (n=34 females and 12 males) subgroups. Predictive equations were derived in the model group and validated with validation subgroup using multiple regression analysis for TBW from impedance.
Results. TBW is best predicted from BIA and weight (R=0.91, SEE=1.4 kg for females and R=0.87, SEE=1.7 kg for males). The regression coefficients did not differ significantly between model and validation subgroups for both females and males. These equations can be used to predict body composition from BIA at 50 kHz in HIV infected Ethiopians.
Conclusion. The predictive equations derived specifically from this population are validated and can be useful in assessing body composition of people living with HIV/AIDS. There is a need to assess whether the equations can accurately detect changes in TBW.
Key words: bioelectrical impedance, total body water, BIA equation, people living with HIV/AIDS, body composition, nutritional assessment
International Journal of Body Composition Research 2007 Vol. 5 No. 2: 73-79
T.C. Mills1, D. Gallagher2, J. Wang2 and S. Heshka2
1Loughborough University , Leics , UK ; 2Body Composition Unit, Obesity Research Center , St. Luke's-Roosevelt Hospital and Columbia University, New York, NY, USA.
Objective. Given the increasing concerns about the levels of obesity being reached throughout the world, this paper analyses the relationship between the most common index of obesity, the BMI, and levels of body fat.
Design. The statistical relationship, in terms of functional form, between body fat and BMI is analysed using a large data set which can be categorized by race, sex and age.
Results. Irrespective of race, body fat and BMI are linearly related for males, with age entering logarithmically and with a positive effect on body fat. Caucasian males have higher body fat irrespective of age, but African American males' body fat increases with age faster than that of Asians and Hispanics. Age is not a significant predictor of body fat for females, where the relationship between body fat and BMI is nonlinear except for Asians. Caucasian females have higher predicted body fat than other races, except at low BMIs, where Asian females are predicted to have the highest body fat.
Discussion. Using BMIs to make predictions about body fat should be done with caution, as such predictions will depend upon race, sex and age and can be relatively imprecise. The results are of practical importance for informing the current debate on whether standard BMI cut-off values for overweight and obesity should apply to all sex and racial groups given that these BMI values are shown to correspond to different levels of adiposity in different groups.
Keywords: obesity; functional form; prediction; gender; race