Methods Of Body Composition Assessment Research Articles

Body composition assessment: an indispensable tool for disease management.

Recent conceptual and technology advancements fostered a rapid development in the field of body composition assessment and provided new and powerful investigative tools. Densitometry, isotopic dilution, bioelectrical impedance, whole-body counting, neutron activation, X-ray absorptiometry, computed tomography, magnetic resonance imaging, and spectroscopy have been the most widely employed methods. The result of this effort is the discovery that body composition at both molecular and cellular or tissue levels is affected by virtually all the pathologic conditions found in medical textbooks. The field is now mature for the clinical translation of this research. Some applications rely on a very solid base and their clinical use has been fully codified. Others still need reference values diversified on a regional and ethnic scale, consensus for interpretation of values, and guidelines for clinical indications. Only after these requirements are satisfied will it be possible to adopt specific practical guidelines, the most reasonable basis for acceptance and accreditation by care providers. Some applications are already being used in several settings. Therefore, establishing the guidelines for clinical application of body composition assessment methods is not only important for physicians and their patients, but is also urgent so as to prevent misuse and to ensure correct communication with the media in this field.

Factors that alter body fat, body mass, and fat-free mass in pediatric obesity.

The purpose of this study was to quantify the effects of exercise treatment programs on changes in body mass, fat-free mass, and body fat in obese children and adolescents. By using the meta-analytic approach, studies that met the following criteria were included in our analyses: 1) at least six subjects per group; 2) subject groups consisting of children in the 5- to 17-yr age range; 3) pretest and posttest values for either body mass, percent body fat, or fat-free mass (FFM); 4) used exercise as a mode of treatment (e.g., walking, jogging, cycle ergometry, high-repetition resistance exercise, and combinations); 6) training programs >or= 3 wk; 7) full-length publications (not conference proceedings); 8) apparently "healthy" children (i.e., free from endocrine diseases and disorders); and 9) published studies in English language journals only. A total of 120 investigations were located that addressed the issue of exercise as a method of treatment in pediatric obesity. Of those, 30 met our criteria for inclusion. Across all designs and categories, fixed-effects modeling yielded significant decreases in the following dependent variables: 1) percent body fat (mean = 0.70 +/- 0.35; 95% CI = 0.21 to 1.1); 2) FFM (mean = 0.50 +/- 0.38; 95% CI = 0.03 to 0.57); 3) body mass (mean = 0.34 +/- 0.18; 95% CI = 0.01 to 0.46); 4) BMI (mean = 0.76 +/- 0.55; 95% CI = 4.24 to 1.7), and 5) VO2max (mean = 0.52 +/- 0.16; 95% CI = 0.18 to 0.89), respectively. Significant differences were found as a function of the type intervention groups (exercise vs exercise + behavioral modification; P < 0.04); body composition assessment methods (skinfold vs hydrostatic weighing, DEXA, and total body water; P < 0.006); exercise intensity (60-65%, vs >or= 71% VO2max; P < 0.01); duration (<or= 30 min vs > 30 min; P < 0.03); and mode (aerobic vs aerobic + resistance training; P < 0.02). Stepwise linear regression suggested that initial body fat levels (or body mass), type of treatment intervention, exercise intensity, and exercise mode accounted for most of the variance associated with changes in body composition after training. Exercise is efficacious for reducing selected body composition variables in children and adolescents. The most favorable alterations in body composition occurred with 1) low-intensity, long-duration exercise; 2) aerobic exercise combined with high-repetition resistance training; and 3) exercise programs combined with a behavioral-modification component.

Field Methods for Body Composition Assessment Are Valid in Healthy Chinese Adults

There is little information on the accuracy of simple body composition methods in non-Western populations. We determined the percentage of body fat (%BF) by isotope dilution [oxygen-18 (H(2)(18)O) and deuterium oxide ((2)H(2)O)] and anthropometry in 71 healthy, urban Chinese adults aged 35-49 y [body mass index (BMI) 18-35 kg/m(2)]. The accuracy of several prediction equations for assessment of %BF from skinfold measurements was evaluated against %BF determined by H(2)(18)O dilution. We also assessed the relationship between BMI and %BF, and the fat-free mass (FFM) hydration coefficient for our population. All skinfold equations yielded means within approximately 2%BF of H(2)(18)O-derived %BF. However, on the basis of residual plot analysis and the 95% confidence interval (CI) for the mean difference between methods, the equations of Durnin and Womersley (for assessment of body density from skinfolds) coupled with that of Brozek et al. (for assessment of %BF from body density) provided the most valid assessment for individuals. In addition, the FFM hydration coefficient averaged 0.734 +/- 0.002 (SEM), indicating that the usually assumed value of 0.732 is appropriate for this population. Finally, although BMI had high specificity (90%) for classifying individuals as having body fat within the normal range (<24%BF for men, and <35%BF for women), it had poor sensitivity (66%) for identifying individuals as having high body fat. We conclude that compared with H(2)(18)O dilution, skinfold thickness can provide an accurate and reliable assessment of body composition in healthy Chinese adults. Furthermore, using the equation of Brozek et al. may be preferable to using Siri's equation to predict %BF from body density in populations in which individuals have >30%BF.

A COMPARISON OF FOUR METHODS FOR ASSESSING PERCENT FAT

Many individuals are concerned about their weight. In an effort to meet this interest, various commercial devices have been developed for assessing body composition. The efficacy of these devices has been questioned. The purpose was to compare one of the newer commercial devices (SCALE) with three common clinical methods of body composition assessment: bioelectrical impedance analysis (BIA), skinfold assessment (SF), and underwater weighing (UWW). The SCALE resembles the typical bathroom scale, however, in addition to weight, it provides an estimate of your percent body fat. Twenty subjects between the ages of 18 and 29 years participated in the study (13 males and 7 females). Each subject was measured by all four methods on the same day. The order of measurement was BIA, SF, SCALE, and UWW.TableA repeated measures ANOVA was used to compare the assessment results. An alpha level of 0.05 was established to determine significant difference. A significant difference (p < .05) was found between the measures of BIA and the SCALE, as well between SF and SCALE. No other individual comparisons or interactions were found to be significantly different. The highest measures for percent body fatness were found with SCALE. The results indicate that the SCALE provided percent body fat results that were not significantly different from those obtained by UWW. Although there were significant differences between the SCALE and SF and BIA, the difference between the means falls within the margin of error typically associated with body composition assessment.

Regarding the validity of methods of body composition assessment in young and older men and women

To the Editor: In their recent paper, Clasey and coworkers ([3][1]) compared several different methods of estimating body fat. The authors took as their reference method a 4-compartment model involving the measurement of body density, total body water, and total body bone ash ([5][2]). They then

Total body water and percentage fat mass measurements using bioelectrical impedance analysis and anthropometry in spinal cord-injured patients

Background and aims: Spinal cord injured patients may be adversely affected by disturbances of nutritional status, particularly malnutrition and fat mass overload. Malnutrition increases the risk for development of pressure sores, and fat mass excess increases the cardiovascular and respiratory risks of these patients, as well as predisposing to the development of diabetes mellitus, pressures sores and bony fractures. Body impedance analysis and anthopometry are easy bedside methods for body composition assessment. The aims of the study were to validate, in 20 spinal cord injured patients, body impedance analysis as a means to estimate total body water, and to validate a skinfold measurement of percentage fat independent of hydration of fat-free mass in the same population.Methods: Total body water was measured by18O dilution as a reference method. Impedance and anthropometric measurements (four different skinfolds) were obtained. The results of total body water given by impedance analysis and calculated with three formulas were compared to the reference method. The fat mass percentage obtained with each of the skinfolds using the 3-compartment Siri's formula was compared to a reference value using the sum of the skinfolds.Results and conclusion: The formula using 100 kHz resistance, height, weight and gender overestimated total body water by only 0.76 ± 1.85 L, with an acceptable concordance with labeled water results. The formula with 50 kHz resistance was less accurate and concordant. Each skinfold may be used for assessing percentage fat mass. Based on these findings, we feel that the triceps skinfold, whose the variability is the lowest compared to the reference values, can be used alone in clinical practice.

Dual-energy X-ray absorptiometry for body composition estimation in Chinese women

To determine whether dual-energy X-ray absorptiometry (DXA) is a valid method for body composition assessment of obese and non-obese subjects. Cross-sectional study. Chinese women living in Hong Kong; 66 of 91 subjects had body mass index (BMI) of >25 kg/m2. Anthropometrics, including body weight, body height, waist and hip girth. Percentage body fat (%BF) and fat-free mass (FFM) from DXA (Hologic 2000 plus, Enhanced Array Whole Body Version 5.63) were compared with that based on a tracer dose of deuterium oxide for the determination of total body water (TBW). In both obese and non-obese subjects, FFMDXA was similar to FFMTBW. The Bland and Altman-type analysis indicated that comparable between-methods differences (mean bias) and limits of agreement were obtained in obese and non-obese subjects for FFM (0.4, between -4.4 and 5.2 kg vs 0.5, between -3.1 and 4.1 kg) and %BF (-0.6, between -7.6 and 6.4% vs -1.2, between -8.6 and 6.2%). The %BF bias was independent of age, BMI, hip circumference, and waist-to-hip ratio, but correlated with waist girth (r=0.24, P=0. 021). The sources of bias are methodological and anthropometric in nature. The between-methods differences, however, are small and clinically insignificant. DXA is a valid method for assessing the body composition of obese patients. This study was supported by a HKU-CRCG grant.

Techniques of Body Composition Assessment: A Review of Laboratory and Field Methods

Body composition is one of the major health-related components of fitness. Thus, it is important for health and fitness professionals to have a general understanding of the most commonly used techniques for assessing body composition. This review presents the developmental background and underlying principles and theory of four laboratory (hydrodensitometry, air displacement plethysmography, isotope dilution, and dual-energy x-ray absorptiometry) and four field (bioelectrical impedance analysis, near-infrared interactance, skinfolds, and anthropometry) methods of body composition assessment. In addition to a description of the methods, the validity, and reliability, strengths, and limitations of each measurement tool are examined. Highlights of the laboratory methods include the relatively new Bod Pod® air displacement device, which is a promising assessment tool more convenient than hydrodensitometry but still lacking substantial validity testing and the ability of dual-energy x-ray absorptiometry to measure regional composition making it an attractive method for clinicians. Advancements in segmental and multifrequency bioelectrical impedance for compartmental analysis have enhanced the value of this field method, but research continues to show that commercially available near-infrared interactance units are invalid. With this knowledge, the clinician and researcher should be able to make an informed decision regarding the most appropriate measurement device for their body composition assessments.

Bioelectric Impedance and Hydrostatic Weighing With and Without Head Submersion in Persons Who are Morbidly Obese

Objective To compare hydrostatic weighing with and without head submersion and bioelectric impedance analysis (BIA) for measurement of body composition of persons who are morbidly obese. Design Body composition was determined using 3 methods: hydrostatic weighing with and without head submersion and BIA. Residual volume for the hydrostatic weighing calculation was determined by body plethysmography. Subjects Subjects were 16 morbidly obese men (142.5 kg mean body weight) and 30 morbidly obese women (125.9 kg mean body weight) living in the Salt Lake County, Utah, area. Morbid obesity was defined as 40 kg or more over ideal weight. Statistical analysis One-way, repeated-measures analysis of variance was followed by Scheffé post hoc tests; body-fat measurement method served as the repeated variable and percentage of body fat as the dependent variable. Men and women were analyzed separately. In addition, degree of agreement between the 3 methods of determining body composition was determined. A regression equation was used to calculate body density for hydrostatic weighing without head submersion. Two new BIA regression equations were developed from the data of the 16 men and 30 women. Results Values for percentage body fat from hydrostatic weighing with and without head submersion (41.8% vs 41.7%, respectively) were the same for men but differed for women (52.2% vs 49.4%, respectively, P<.0001). Values for body fat percentage measured by BIA were significantly lower for men (36.1%) and women (43.1%) (for both, P<.0001) compared with values from hydrostatic weighing methods. BIA underpredicted percentage body fat by a mean of 5.7% in men and 9.1% in women compared with the traditional hydrostatic weighing method. Applications/conclusions BIA tended to underpredict the measurement of percentage body fat in male and female subjects who were morbidly obese. Hydrostatic weighing without head submersion provides an accurate, acceptable, and convenient alternative method for body composition assessment of the morbidly obese population in comparison with the traditional hydrostatic weighing method. In population screening or other settings where underwater weighing is impractical, population-specific BIA regression equations should be used because general BIA equations lead to consistent underprediction of percentage body fat compared with hydrostatic weighing. J Am Diet Assoc. 1998;98:869-875.

Validity of body composition assessment methods for older men with cardiac disease.

This study was designed to determine which of several body composition assessment methods was most accurate for patients with cardiac disease for the purpose of outcome measurement. Six body composition assessment methods were administered to each of 24 men with cardiac disease. Methods included circumference measurement, skinfold measurement, near-infrared interactance via the Futrex-5000, bioelectrical impedance via the BioAnalogics ElectroLipoGraph and Tanita TBF-150, and hydrostatic weighing, the criterion measure. A repeated measures analysis of variance indicated no significant (P > .05) difference between circumference and skinfold measurements compared to hydrostatic weighing. Near-infrared interactance presented the best standard error of estimates (3.5%) and the best correlation (r = .84) with hydrostatic weighing; however, the constant error was 3.76%. Bioelectrical impedance measured by the ElectroLipoGraph and TBF-150 instruments significantly underestimated percent body fat by 8.81% and 4.8%, respectively. In this study of middle-aged to older men with cardiac disease, the best method for determining body fat was circumferences. This technique was accurate, easy to administer, inexpensive, and had a lower error potential than the other techniques. Skinfold measurements were also closely related to hydrostatic weighing, but should be performed only by experienced practitioners because there is a greater potential for tester error in certain patients. In the future, near-infrared interactance measurements may be a viable technique for body composition assessment in patients with cardiac disease. However, algorithms specific to the population of patients with cardiac disease being tested must be developed before this technique can be routinely recommended for body composition assessment. Bioelectrical impedance assessment by either method is not recommended for patients with cardiac disease, as it consistently underestimated percent body fat when compared to hydrostatic weighing in this population.

Changes in Body Composition Measures of Cadets During a Twelve-week Training Program

LEARNING OUTCOME: To describe different methods of body composition assessment to estimate percent body fat of cadets before and after a 12-week long law enforcement training program A component of a 12-week regional law enforcement training program includes fitness training, but no nutrition intervention. Conventional fitness assessment of the program includes aspects of muscle strength and cardiovascular fitness; however, assessment of body composition is not usually performed. To improve the cadets fitness, the program incorporates one hour of physical training (PT) four days/week. To better evaluate the status of cadets entering the program and the effects of training, we assessed body composition in the first and last week of the program. Measurements included height, weight, a 3-site skinfolds (Jackson & Pollock) and bioelectrical (BIA, RJL) resistance and reactance. Calculated variables evaluated included body mass index (BMI) and body fat by both skinfolds (BF-S) and by BIA (BF-BIA). A comparison of these variables for the first and last weeks were made only for paired data. Entering cadets (age = 28.3±0.65) had a BMI of 30.1±0.6, a BF-S of 24.3±0.6, and BF-BIA of 29.2±0.7. The pre-post comparison showed modest reduction in body weight (−0.62±0.34 kg) and BMI (−0.18±0.11 kg/m 2). Small but significant (p>0.05, paired t-test) decreases were found for BF-S (−0.65±0.25 % fat) and BF-BIA (2.56±0.30 % fat). These data indicate that many entering cadets are at moderate risk (BMI of Grade II or above). Modest reductions in body fat were associated with small increases in lean body mass. Alone, PT successfully lowered body fat but only at minimal levels. These findings support the introduction of nutritional intervention by menu modifications and individual counseling to reduce the risk of disease

Validation of Body Composition Assessment Techniques in the Dialysis Population

Assessment of body composition remains a goal for the routine assessment of nutritional status of patients on long-term dialysis. Methods generally available for estimation of body fat in healthy individuals are limited by practicality and availability for use in this patient population. Anthropometry, which is cost effective and easy to perform, is limited by the lack of appropriate reference standards for patients on dialysis and artifact caused by hydration status. Bioelectrical impedance affords new opportunities for non-invasive assessment of fluid volume, its distribution, and body cell mass; estimation of fat-free mass and body fat can be affected by hydration status. Dual x-ray absorptiometry permits estimation of bone status and fat mass because changes in hydration status are reflected in estimates of fat-free mass. Evaluation of validity of techniques for fluid status and body composition assessment requires the use of appropriate reference methods and proper statistical procedures to examine error, not only between groups, but by individual. Use of body composition assessment methods together with biochemical measurements will enhance the nutritional assessment of end-stage renal disease patients on long-term hemodialysis.

Bias between two reference methods of body composition assessment in elderly men

Bias between two reference methods of body composition assessment in elderly men

Body composition and menstrual function in athletes.

The problem of menstrual dysfunction in athletes was recognised at about the same time as a theory was developed that a critical fat level was necessary for the onset and maintenance of menstrual function (17% and 22% of bodyweight, respectively). This theory was acceptable because of the frequency of leanness in athletes experiencing menstrual dysfunction and because of the role of adipose tissue in the intraconversion of hormones which could affect hypothalamic and pituitary regulatory centres. Research on this topic has been hampered by the extensive use of surveys, confining sampling to specific sports, use of inaccurate methods of body composition assessment, and lack of data on hormonal changes. Studies using appropriate body composition measures do not support the critical fat theory, but they do not exclude a role for body composition changes in the regulation of menstrual function. The probability of finding menstrual dysfunction in very lean athletes is high, but not absolute, and there is no assurance that dysfunction will improve merely by increasing bodyweight. Perhaps of more concern, however, is recent research on very lean, long term amenorrhoeic athletes who train intensely and show a loss of bone mineral, apparently related to low oestrogen levels. This mineral deficiency is apparently a factor in stress fractures. The bone mineral content of these athletes is similar to that of post-menopausal women susceptible to osteoporosis. Although the loss of bone due to short term amenorrhoea may be reversible, the prognosis for a long term deficiency is not presently known.

Estimation of body volume by underwater weighing: description of a simple method.

Estimation of body volume by underwater weighing: description of a simple method.