Appropriate technology in body composition: a brief review
Author:Durnin JV
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Abstract:This paper attempts to link the particular method to be used for body composition measurements to the objectives of the study. There is often inadequate attention paid to the real requirement for different degrees of precision, and excessive amounts of time and labour are spent on quite unnecessary minutiae of technology. Special attention is paid to bio-electrical impedance, skinfold thicknesses, stable isotope techniques, and methods for assessing fat distribution.
Asia Pac J Clin Nutr. 1995;4(1):1-5.doi:
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Body composition - what is measurable?
Author:Beddoe AH
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Abstract:In 1878 Behnke noted that 'nothing is measured with greater error than the human body'. Over the intervening period measurement techniques have been developed which range from the relatively simple anthropometric methods to those based on sophisticated radiation and nuclear physics technologies. Nevertheless, despite the undoubted progress, it is important that we ask ourselves whether Behnke's observation might still have some validity. Many reviews have concentrated on the problems and limitations of given techniques with particular emphasis on achievable precision (because precision is easy to measure). However a straight-forward analysis of published data, especially of that relating to indirect techniques, shows that measurement precision is frequently small in magnitude compared to biological precision, the latter being simply a reflection of Nature's refusal to conform to imposed regression relationships. In this paper the body composition technologies are reviewed in the context of achievable accuracy and precision.
Asia Pac J Clin Nutr. 1995;4(1):7-10.doi:
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Bone densitometry: relevance to health care
Author:Seeman E
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Abstract:Since low bone density is a risk for fracture, the relevance of bone densitometry as a basis for health care assessment needs to be elucidated. Most patients with fractures are in the lower two quartiles of bone density. Bone densitometry can be used to provide a quantitative estimate of fracture risk and a measurable response to aging, disease or medical treatment in the individual. Some difficulties concerning the efficacy of screening the whole population are discussed, for instance in terms of the success of treatment. Screening to prevent fractures should be advocated in women considering HRT. Research into defining bone quality is needed, as are further studies on the pathogensis of low bone density and on the contributions of low peak bone density and rates of loss to bone density in adults.
Asia Pac J Clin Nutr. 1995;4(1):11-13.doi:
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Using low-cost body composition technology for health surveillance
Author:Prijatmoko D, Strauss BJ
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Abstract:Standards for skinfold thickness and abdominal/hip ratio have been published which facilitate the evaluation of body composition as an index of health risk and can be used to determine the degree to which lifestyle modification may be required. This study provides information on body composition including fat distribution in a Javanese population living in Jember, Indonesia. The sample consisted of 122 adults (71m, 51f), aged between 20 and 60 years, selected randomly from the Indonesian Government identification list. Data collected were compared with that obtained from the Melbourne Body Composition Study a representative sample of Australians living in Melbourne. Body fatness was assessed from the skinfold measurement at four sites: triceps, biceps, subscapular and supra iliac and converted using the Durnin and Womersley equation. Body fat distribution was assessed from the ratio of the smallest waist and the maximal gluteal circumference. The body composition profile of these two populations were also measured by the BIA method. The cross-sectional data showed that there are significant differences between the two populations in the degree of fatness and fat distribution. However, Melbourne Australians and Jember Indonesians were similar in biceps skinfold thickness of males and females, and in the subscapular skinfold thickness in females. The use of skinfold thickness of measuring body composition differences between populations is a valuable instrument, provided more than a single site is used. A low-cost technique like BIA provides additional information. A single skinfold thickness may still be valuable provided standards appropriate to the ethnic group are used. The difference in body composition profiles between the two populations suggests the evaluation of the association between fat mass and fat distribution and health risk should be based on standards appropriate to the ethnic group studied. This requires longitudinal studies of body composition, and health outcome specific to each population.
Asia Pac J Clin Nutr. 1995;4(1):15-17.doi:
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Low-cost appropriate technologies for body composition assessment: a field researcher's view
Author:Solomons NW, Mazariegos M
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Abstract:The field setting, as distinct from the clinical and laboratory settings, relates to the study of populations and subpopulations. It can involve either free-living or institutionalized individuals. The concept of 'body composition' goes beyond the traditional assumptions of screening anthropometrics, although it includes many of the same measures. The principal practical considerations for the selection of measurement techniques are ethics and cost. The quantitative considerations are the precision and accuracy of the measures. The biological considerations relate to the interpretation of the measure in terms of underlying body constituents; do the values mean what we hope them to mean?
Asia Pac J Clin Nutr. 1995;4(1):19-22.doi:
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Clinical needs and opportunities in assessing body composition
Author:Tanphaichitr V, Leelahagul P
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Abstract:Protein-energy malnutrition (PEM) and obesity are hazardous to health with high morbidity and mortality rates. The assessment of body composition is essential to prevent, diagnose and determine the severity of these disorders as well as their response to therapy. Body weight is the sum of fat and fat-free mass (FFM) whereas its chemical model consists of triglyceride, protein, water, and minerals. Thus one must recognize the appropriate method to assess each compartment of body composition. In clinical practice, the method must be simple, accurate, noninvasive and inexpensive. Body mass index (BMI) is a practical anthropometric parameter to assess protein-energy status in adults because it can easily be calculated from weight in kg divided by (height in meter), and correlates with fatness and mortality. Total body fat can be estimated by measuring the amount of subcutaneous fat by measuring the thickness of the subcutaneous fat layer at different sites of the body by a skinfold caliper or near-infrared interactance. A high waist-over-hip circumference ratio (WHR) can be used to diagnose abdominal obesity. Upper arm muscle circumference can be employed to measure muscle mass. However, whenever these methods are used to assess body composition their limitations should be recognized.
Asia Pac J Clin Nutr. 1995;4(1):23-24.doi:
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The elite athlete - assessing body shape, size, proportion and composition
Author:Kerr DA, Ackland TR, Schreiner AB
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Abstract:In the quest to optimize performance of the elite athlete the sport scientist has sought to determine the ideal physique for a given sport or event. For some sports, specific structural characteristics offer definite performance advantages; for example in rowing, in addition to height, a large arm span has been identified as important. In other sports. such as long distance running, low levels of adiposity or 'fatness' appear to be linked with faster running times. There are four areas where appraisal of the athlete's physique can provide useful information: (1) identification of talented athletes; (2) to assess and monitor the growing athlete; (3) to monitor training and performance; and (4) to determine 'race weight' in weight-category sports. As a research tool a particular method must be reliable and valid. Other considerations include how expensive the method is, if it is suitable for a field situation and if large amounts of data on a number of subjects can be collected quickly. The method should be safe for both the athlete and the tester and provide useful feedback for the athlete or coach. Anthropometry, with training is able to fulfil most of these criteria and is the most widely used method of physique assessment in sports science. Large anthropometric data bases have been collected on elite athletes at Olympic games and world championships according to a standard protocol. Kinanthropometry, which has developed from anthropometry, is concerned with measurement and evaluation of different aspects of human movement and individual variation in body shape, size, proportion and composition. For the assessment of adiposity a sum of skinfolds, usually over six sites, is most commonly used rather than percentage body fat formulae. Muscle mass can be assessed indirectly through girth and corrected girth measurements. Limb lengths and breadths are used to assess skeletal structure and proportional differences in limb size. The anthropometric methods most commonly used to describe the physique of the athlete, which appraise shape, size, proportion and composition, will be discussed.
Asia Pac J Clin Nutr. 1995;4(1):25-29.doi:
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Role of body protein as a prognostic indicator in wasting disease
Author:Allen BJ, Pollock CA, Russell J, Oliver C, Smith R
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Abstract:Malnutrition is associated with many chronic diseases, though its extent and effect is not well known. Measurement of body protein provides a quantitative and reproducible means of monitoring malnutrition. Results for anorexia nervosa, end stage renal failure value and asymptomatic and symptomatic HIV positive subjects are presented to show that, with the exception of asymptomatic HIV subjects, substantial protein depletion does occur. A more difficult problem is to determine the relation between body protein, the effects of treatment and prognosis. In the case of CAPD patients, 20% protein depletion was found to be associated with a poor prognosis. For anorexia nervosa subjects, readmission probability was found to be correlated with body protein. However, monitored refeeding and exercise achieved a more normal body composition and quality of life. The critical effect of protein depletion in AIDS remains to be determined, but once ascertained, the role of enteral and parenteral supplementation can then be quantitatively examined.
Asia Pac J Clin Nutr. 1995;4(1):31-33.doi:
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Body composition measurement in normal children: ethical and methodological limitations
Author:Baur LA
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Abstract:There are significant ethical. practical and theoretical issues that need to be considered when measuring body composition in normal children. For example, when evaluating the use of techniques that involve ionizing radiation, then the benefit to the volunteer subject, or society at large, needs to be balanced against the likely harm to the subject. For children, the detriment per unit dose may be two to three times larger than that for young adults. At present the decision as to the acceptable radiation dose limit for healthy children undergoing research studies remains debatable. Most techniques for measuring body composition require specific validation of their precision and accuracy when used with small subjects; adaptation of existing methods may thus be necessary in order to measure children. In addition, techniques such as densitometry and dual energy X-ray absorptiometry may be impractical for use in young children. A major theoretical issue to be considered is that most body composition techniques assume a constant density or chemical composition of the fat-free mass (FFM). However, the FFM in children does not consist of fixed proportions of water, protein and mineral; rather, the proportions of these change during growth, with water content decreasing and protein and mineral content increasing. Caution must therefore be used in the application of adult-derived body composition constants and equations to children.
Asia Pac J Clin Nutr. 1995;4(1):35-38.doi:
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Body composition measurement: the challenge in the unwell child
Author:Bines JE
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Abstract:The assessment of body composition in the unwell child presents a significant clinical and technological challenge. The effect of disease adds to the complex series of changes in body composition that occur during normal growth and development. To assess the progress of disease or the effect of therapy, repeat measurements of body composition in a single patient may be desirable. However, repeat studies using some methods may not be appropriate due to the potential risks associated with repeated radiation exposure in this young age group. The ability to accurately detect changes in body composition between studies depends on the precision of measurement. Unfortunately, there may be a reduction in precision of measurement with smaller patients when the ability for detecting small changes is of particular relevance. Adequate and correctly timed fluid samples required for dilution studies may be difficult to obtain in the unwell infant and child. New equations or modification of 'adult' equations need to be devised to interpret raw data and these need to be validated in patients of different ages and sizes and in children with different diseases states. Specific challenges related to some common and uncommon paediatric diseases are discussed.
Asia Pac J Clin Nutr. 1995;4(1):39-42.doi:
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Physical activity and movement in children: its consequences for growth and development
Author:Hills A
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Abstract:The value of physical activity to health and fitness and normal growth and development is undisputed. In contrast, lack of exercise or excesses in physical activity can be harmful to the growth and development process. Normal physical maturation represents a succession of events which appear in the same sequence in all individuals but vary in both starting point and speed of occurrence. It is often difficult to distinguish the effects of regular physical activity upon fitness from the changes associated with growth and maturation. An integral component of the relationship between health and fitness is body composition. Maintenance of a desirable body composition is an integral component in health status and in the evaluation of health, fitness and physical performance of individuals. Traditionally, discussions that have considered the benefits of regular physical activity have referenced cardiorespiratory and other components of physical fitness such as muscular strength and endurance. More recently, body composition has received considerable attention with numerous individuals of all ages preoccupied with body characteristics such as body fat and muscularity. Less recognition has been given to the role that exercise plays in the maintenance of skeletal health and the potential benefits to be gained by this component of body composition. This is gradually changing with the knowledge that osteoporosis is mediated by nutritional, physical activity and hormonal influences and that inappropriate physical activity can be potentially hazardous to the immature and mature skeleton. Regular physical activity that provides an appropriate weight bearing stimulus is critical for the maintenance of desirable body composition including normal skeletal health, irrespective of age or sex. Benefits derived for body composition are equally important to personal health as the development of other components of fitness.
Asia Pac J Clin Nutr. 1995;4(1):43-45.doi:
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Can total body nitrogen be measured in newborn infants?
Author:Borovnicar DJ, Stroud DB
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Abstract:The feasibility of using prompt in vivo neutron activation Analysis (IVNAA) of nitrogen to measure the total body nitrogen (TBN) of newborn infants has been investigated by redesigning and recalibrating an existing IVNAA facility used for the measurement of TBN in adults. Repeated 1000 sec measurements of an infant phantom (4kg wt: 80g N) yielded an average measured value that is within 0.2± 1.8% (1xSD) of the actual value and a precision of 7.9% (CV) for a single measurement. Preliminary investigations indicate that the whole body radiation dose is no greater than 1 mSv (Q=20) for a 1000 s irradiation. It is proposed, and in part demonstrated, that measurement precision can be reduced to ≒5% by (i) using a graphite neutron reflector positioned over the infant to increase the in vivo thermal neutron flux, and (ii) doubling the number of NaI(TI) detectors.
Asia Pac J Clin Nutr. 1995;4(1):47-50.doi:
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Evaluation of multiple frequency bio-electrical impedance analysis in paediatric subjects
Author:McCarthy JM, Ward LC, Holt TL, Shepherd RW
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Abstract:The efficacy of multiple frequency bio-electrical impedance analysis (MFBIA) at discrete frequencies in predicting body cell mass, total body water, and fat-free mass compartments was investigated in healthy (n=30) and diseased (n=40) paediatric populations. Correlation coefficients achieved by comparing MFBIA with reference techniques using Deming's regression analysis were in excess of 0.9, but were not superior to those achieved comparing reference techniques with the traditional BIA application at 50 kHz. Applying the 95% limits of agreement procedure to the results showed that the agreement between the techniques was not sufficient for the technique to be of value in individual body composition assessments. The use of MFBIA at discrete frequencies does not improve the accuracy of estimations of body compartment sizes in paediatric subjects compared with those obtained with BIA at 50 kHz.
Asia Pac J Clin Nutr. 1995;4(1):53-54.doi:
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Body composition and the aged: what needs to be measured?
Author:Steen B, Gause-Nilsson I, Bosaeus I, Alpsten M
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Abstract:Within the gerontological and geriatric population studies in Gothenburg, Sweden, body composition studies have been performed with a four-compartment model (using whole-body potassium 40 counting and dilution of isotope labelled water) for two decades, the impedance method for some years and total body nitrogen determination by in vivo neutron activation technique for the last few years. Examples are given from a longitudinal study in 70-year-olds followed at the ages of 75, 79 and 81 years, and from a recent study of 75year-olds.
Asia Pac J Clin Nutr. 1995;4(1):55-56.doi:
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Body composition and aging: a practising clinician's point of view
Author:Prinsley DM
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Abstract:Human size and shape vary widely. Relative obesity or apparent under nutrition may not limit survival into old age. Normal body appearance can mask gross malnutrition, particularly mineral and vitamin deficiency, problems of measurement in the elderly. Obesity is associated with joint degeneration and systemic disease but with reduced incidence of fractures. Undenutrition is associated with skin breakdown, poor wound healing and fractures. Body composition changes due to disease include dysphagia, myxoedema, anaemia, chronic cardiac and renal disease. Skeletal changes include osteoporosis and Paget's disease. Body composition can change due to treatment, control of dietary energy intake and tube-feeding.
Asia Pac J Clin Nutr. 1995;4(1):57-58.doi:
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Body composition in MesoAmerica
Author:Solomons NW, Mazariegos M
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Abstract:The fundamental paradigm for the region is short stature. Adult height is on the order of 160 cm for men and 140 cm for women. The timing of this delayed growth has been fixed to the first two years of life, when as much as 2 Z-scores of stature may be loss to the median of the NCHS reference. In the elderly of the region, we have the issue of being initially short and then suffering further loss of stature with age. The height/armspan ratio has proven instructive for exploring that change in height with age. It appears to be less than in Europeans. Demands of a rigorous agricultural lifestyle, the energy content and density of the diet, and the ravages of recurrent infection and parasitism comprise the environmental determinants of body composition in poor MesoAmerican population. They are conducive to a low storage of fat, with lean body mass being subject to response to infections. Because of the basic short stature but muscular maturity of children and adults, one questions whether the assumptions of proportionality of weight for height from the NCHS reference data apply, or whether MesoAmericans should be normally greater in weight for height than a comparably short North American. For some at the lower end of the stature scale, no international reference standards actually exist for adults. All than can be measured with microtoise, calliper, flexible tape and balance has long been recorded in MesoAmerican populations. Certain high-cost and facility- dependent technologies, such as nuclear magnetic resonance imaging and whole-body neutron activation analysis, are beyond the scientific economies of any part of the region. Dual energy x-ray absorbitometry instruments are available for clinical diagnosis in Mexico, Guatemala and Costa Rica, and could be turned to research ends. Underwater weighing has been practiced variously in MesoAmerica. Researchers in Guatemala have pioneered in the investigative use of bioelectrical impedance analysis to all ages from low-weight newborns to the very elderly; currently, introduction of the multifrequency BIA to Guatemalan laboratories, and application to the very young in dehydrated (diarrhoea) and overhydrated (kwashiorkor) states are being conducted.
Asia Pac J Clin Nutr. 1995;4(1):59-62.doi:
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Body composition of ethnic groups in the US
Author:Roche AF
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Abstract:Total body composition has not been reported from national samples of ethnic groups in the US but the data being recorded in the Third National Health and Nutrition Examination Survey include anthropometric variables and bioelectric impedance that jointly would allow the prediction of fat-free mass and other body composition variables for individuals. If these values were used in combination with the sample weighing coefficients, they could provide national estimates for composition values in whites. Afro-Americans and Hispanic-Americans. Despite the limitations of the reports currently available. data from relatively large groups will be summarised and ethnic comparisons will be made taking into account the procedures by which the data were obtained. Data for regional body composition. mainly skinfold thicknesses and circumferences, arc much more plentiful. They allow the evaluation of possible secular trends and of fat patterning within ethnic groups and the possible interplay of genetic and environmental influences.
Asia Pac J Clin Nutr. 1995;4(1):63-67.doi:
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Body composition in Aboriginal Australians
Author:Rutishauser IH
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Abstract:The anthropomorphic features of Australian Aborigines have been described, measured and reported in considerable detail by explorers, anthropologists, anatomists and medical practitioners. These reports have provided evidence that some aspects of Aboriginal physique differ considerably from those of Europeans. For example, it has been reported that Australian Aborigines of both sexes have relatively shorter trunks and longer legs than almost every other ethnic group, that body proportions differ less between males and females, and that traditionally Australian Aborigines had a lower weight for stature than Europeans of the same age and sex. Less information exists on their body composition. Available data, however, indicate that there may also be differences in body fat distribution, but not in the amount of fat-free mass (FFM) per unit of stature, between Australian Aborigines and Australians of European origin An analysis of the available data on body composition suggests that the very low body mass index (BMI) values observed in apparently healthy Aborigines, and the different relationship in this ethnic group between BMI and the amount of subcutaneous fat, are more likely to be due to a more central body fat distribution than to differences in skeletal body proportions between Australian Aborigines and Australians of European origin.
Asia Pac J Clin Nutr. 1995;4(1):73-76.doi:
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Technology in body composition: considerations for a traditional, elderly Indonesian population
Author:Oenzil F
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Abstract:Body composition has been measured in a group of elderly people living in nursing home care in West Sumatra, Indonesia. Anthropometric techniques were used to measure height, weight, waist and hip circumference, and skinfolds at four sites (triceps, biceps, suprailiac and subscapula). Body fat was determined with the equations of Durnin and Womersley, although difficulties were encountered because of the age and leanness of some of the subjects. The average age of the subjects was 73.0± 7.5 years (n=20) and 73.4± 5.4 (n= 15) for males and females respectively. The average body mass index (BMI) was 18.2 kg/m2 for both groups. The mean total body fat and waist/hip ratio for the males was 8.8 kg and 0.86; corresponding results for the females were 12.3 kg and 0.77. The results demonstrate the limitations of these techniques, when they are applied to an elderly population for which appropriate standards are not available.
Asia Pac J Clin Nutr. 1995;4(1):77-78.doi:
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Influence of body composition on risk factors for coronary heart disease in Thai women
Author:Leelahagul P, Soipet S, Achariyont P, Pakpeankitva
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Abstract:Height, body weight, body mass index (BMI), waist-to-hip circumference ratio (WHR), and body fat (BF were determined in 453 female Ramathibodi Hospital Staff, aged 19-61 years. These mean (±SEM) anthropometric parameters were 1.55+0.002 m, 55.1±0.4 kg, 23.0±0.2 kg/m2, 0.82±0.003, and 21.2±0.2 kg, respectively. The prevalences of overall obesity (BMI >= 25 kg/m2) and abdominal obesity (WHR>0.8) were 27.0 and 54.1 %, respectively. Their serum TC, LDL-C, TG, TC/HDL-C, LDL-C/HDL-C, apo B and FBG increased with overall obesity based on BMI or BF whereas opposite results were observed for serum HDLC and apo A-l levels. Except serum TC, LDL-C, and apo A-l levels, other biochemical parameters were also influenced by abdominal obesity based on WHR.
Asia Pac J Clin Nutr. 1995;4(1):79-80.doi:
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Anthropometric indices among adult Melbourne Chinese Australians
Author:Hsu-Hage BH, Wahlqvist ML, Idema KT
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Abstract:Anthropometric indices of adult Chinese living in Melbourne, Australia, were studied. 540 (271 men and 269 women) adult Melbourne Chinese were recruited for a study of food habits and cardiovascular risk factor prevalence; all had stature, body weight and waist and hip circumferences measured. Body mass index and waist-to-hip ratio were estimated, along with fat-free mass, total body fat and the percentage body fat, using established or published formulae. Stature was negatively associated with age and positively related to education level. The Australian-born Chinese had the greatest anthropometric indices; those born in China and Hong Kong had a similar anthropometric profile; the anthropometric profile of Vietnamese Chinese was similar to that of their Australian born counterparts and was significantly greater than that of their counterparts born in China and Hong Kong. Our study suggests that a favourable environment can promote full genetic potential in growth, as evident in the Australian-born Chinese. Those born in Vietnam appeared to have taken full advantage of the Australian environment and showed an elevation of body composition.
Asia Pac J Clin Nutr. 1995;4(1):81-87.doi:
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Seasonal changes in body weight, body mass index (BMI) and body composition of rural Beninese women
Author:Schultink W, Raaij JM
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Abstract:Seasonal changes in body weight and body mass index (BMI) of two groups of rural Beninese women were investigated throughout a one-year cycle. Average body weight showed seasonal fluctuations of 1.4 kg in South Beninese women and of 3.8 kg in North Beninese women. Weight changes were reflected in changes of BMI distribution. In a sub-group of South Beninese women (n=24) body composition was estimated in a pre- and post-harvest season using D2O dilution. bio-electrical impedance (BIA). skinfold measurements. and BMI equations. Seasonal weight change in the sub-group was 0.8± 1.6 kg (p<05). Each method indicated that there was a significant change in fat-free mass (FFM) but not in fat mass from the pre-harvest to the post-harvest season. Fat mass assessed by D2O was 12.3± 3.3 kg which was significantly lower(p<01) than the assessment by the other three methods. The difference between D2O and skinfold method was 1.5± 2.1 kg. between D2O and BIA 1.8± 2.1 kg, and between D2O and BMI 2.0± 2.0 kg. It is concluded that various methods to estimate body composition are not interchangeable in field conditions.
Asia Pac J Clin Nutr. 1995;4(1):89-94.doi:
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The interplay between nutrition and body composition
Author:Fürst P, Leweling H
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Abstract:Stress and malnutrition are associated with altered body composition. Extracellular fluid increases, with wt gain, but in response to stress BCM may gradually shrink with wt loss. In catabolic illness there is extracellular fluid expansion and erosion of AT and BCM. In stress, net loss of body fat was associated with interstitial accumulation of lipids preferentially in muscle, although BIA did not indicate increased fat and decreased water. Severe trauma and sepsis exerted prolonged effects on tissue electrolyte and water metabolism. Treatment of the critically-ill is of the primary illness. Nutritional therapy is an effective adjunct except in chronic sepsis or critical patients with MOF with great wt and protein loss. Glutamine dipeptides may help with cellular hydration and address catabolic changes.
Asia Pac J Clin Nutr. 1995;4(1):95-101.doi:
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Measuring fat and fat-free mass: clinical significance and limitations
Author:Strauss BJ
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Abstract:Measuring body composition is part of clinical nutritional assessment. Simultaneous measurements of fat mass, and fat-free mass, or, preferably, the components of fat-free mass, will yield the most clinical information, but may be limited by laboratory availability. In obese subjects, measurements of fat mass and fat distribution is complemented by a simultaneous assessment of cell mass or total body protein, since management will involve following changes in all of these parameters. Similarly, in osteoporosis, assessment of fat mass and distribution at the same time as bone mass and density, where hormonal replacement therapy has been instituted is a necessary pan of the total management of the patient. Since fat distribution has been recognised as an important indicator of health risk, it has become increasingly important to know how to quantify risk and risk change in individuals with abdominal fat distribution. Little information is available about this, or the risks peculiar to peripheral fat distribution. As compartmental models of body composition become more complex, changes in these compartments in various illnesses are becoming clearer. The use of IVNAA for measuring total body protein changes in haemodialysis, and alcoholic cirrhosis, and the recent development of multifrequency BIA to assess extracellular water provide good examples. Although many hospitals clinics now have DEXA and BIA available, body composition laboratories per se are still a rarity, limiting clinical measurements to anthropometry. The errors involved in measurement using the various techniques mentioned still do not allow assessment of short-term changes in fat mass, or the components of fat-free mass.
Asia Pac J Clin Nutr. 1995;4(1):103-104.doi:
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Body composition of HIV-infected male adults with wasting syndrome
Author:Ellis KJ, Shypailo RJ, Pivarnik JM, Jenks BH, Walz
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Abstract:Chronic weight loss is a common characteristic of HIV infection; its full etiology remains unknown. We report body composition measurements for 39 adult males with wt loss >= 10% or a body mass index (BMI) below 19.8 kg • m-2 while receiving stable antiretroviral therapy, and no recent history of opportunistic infection, malignancy, Kaposi sarcoma, or therapy with anabolic agents. CD4+ counts ranged from 2 to 531; 30 subjects having counts <= 200. Body composition was measured by 40K counting, dual-energy X-ray absorptiometry (DXA), and anthropometry. The reference body composition measures were total body potassium (TBK), lean tissue mass (LEAN), fat mass (FAT), and percentage body fat (%FAT). In addition, nutritional assessment was based on a 2-d food diary. The mean TBK was 90.2% ± 10.8% of normal controls, while the %FAT averaged only 14.4% ± 5.3%, also below the normal range. Reasonable estimates of these body composition compartments were obtained using a combination of BMI, mid-arm circumference (MAC), and triceps skinfold measurements (TSF).
Asia Pac J Clin Nutr. 1995;4(1):105-108.doi:
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Aspects of body composition in human immunodeficiency virus (HIV) infection
Author:Oliver CJ, Allen BJ, Gold J
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Abstract:In the mid-1980s, body composition studies of symptomatic AIDS patients, utilizing total body potassium counting and isotope dilution. indicated that the pattern weight loss observed in advanced HIV infection was similar to a stressed or injured state, rather than one of starvation. A disproportionate depletion of body cell mass (of which skeletal muscle is a major component), relative to loss of body weight, was seen along with a relative expansion of the extracellular fluid volume The same researches observed that this decline in body cell mass was predictive of mortality. Cross-sectional studies in HIV infection have also indicated that a reduction in body cell mass can occur early in the disease process; these studies utilising bioelectrical impedance analysis as a means of body composition assessment.
Asia Pac J Clin Nutr. 1995;4(1):109-111.doi:
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Body composition in anorexia nervosa - changes with treatment, determinants and techniques
Author:Russell JD, Allen BJ, Vizzard J, Arthur B, Mira M,
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Abstract:Body fat, total body water and totally body nitrogen were estimated twice before and after refeeding in 32 patients with anorexia nervosa. Body composition was estimated once in 29 normal controls using the techniques of anthropometry, impedance and IVNCA. The influence of weight gain and other variables, ie psychological status, biochemical parameters, exercise and dietary composition, on protein repletion was examined. Methods of assessment of body composition were compared. The results demonstrated that in anorexia nervosa patients, protein was more completely replenished than fat when patients had reached 85% of average body weight for height and age. Weight gain was the only determinant of protein gain. There was no correlation with psychological, biochemical or exercise status nor with dietary composition. Direct methods, ie deuterium dilution and IVNCA, were shown to be preferable in determination of body composition in anorexia nervosa.
Asia Pac J Clin Nutr. 1995;4(1):113-115.doi:
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Body composition studies with intravenous nutrition
Author:Smith RC
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Abstract:Intravenous nutrition is a complex nutritional support system which is used for patients who are unable to take food through the normal enteric route. The nutritional protocols are complex and the patients being studies have many complicating factors which make determination of outcome difficult to measure. Body composition measures have proven to be very accurate in determining appropriate protocols for patient care. Because most of the patients being studied have a short term nutritional problem, appropriate period of study was found to be two weeks. In this model we have been able to consistently measure small changes in groups of between 10-15 patients. A large change which may occur in a more severe case could be demonstrated in simple patients. This model has demonstrated that 0.3 g of nitrogen per kg per day and 40 kcal of energy are necessary to maintain body composition over a 14 day period. This nutritional input appeared to be similar whether the patient was in the post-operative non septic state or in the pre-operative depleted condition. Studies were undertaken to show that nutritional benefit of changing from all-glucose to a lipid containing solution did not affect the nutritional outcome of therapy. The nutritional gains seen over the first 14 day period were sustained in a longer study of a small group of patients who were studied at two weekly intervals for 3 months. Subsequent to these studies it has been considered important to determine whether peripheral intravenous nutrition would be as effective as central intravenous nutrition. By adjusting the nutritional protocol such that it fulfilled the rules obtained by central intravenous studies we have demonstrated that peripheral iv nutrition can maintain body composition but that the amount of glucose required for this to occur is at least 30% of non-protein calories.
Asia Pac J Clin Nutr. 1995;4(1):117-123.doi:
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Body composition studies in intensive care patients: comparison of methods of measuring total body water
Author:Plank LD, Monk DN, Gupta R, Franch-Arcas G, Pang J
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Abstract:Changes in total body water (TBW) were monitored in 12 critically-ill intensive care patients using four independent methods. Over the 10-day study period TBW measured by tritium dilution changed from 51.3 ± 2.5 (SEM) kg to 43.6 ± 2.3 kg, an average loss of 7.7 ± 0.8 kg. A six-compartment model of the body incorporating measurements of protein by in vivo neutron activation analysis and fat and bone mineral by dual-energy X-ray absorptiometry was used to determine TBW by difference from body weight. The 10-day change in TBW measured by this approach was 8.4 ± 0.9 kg which correlated well with the tritium dilution changes (r=0.84, P<0.01, SEE=1.83 kg). The changes measured by single frequency and multi-frequency bio- electrical impedance analysis were not significantly different from the tritium results (9.7 ± 1.3 and 8.2 ± 0.8 kg. respectively) although the prediction errors were high for both methods (SEE=3.29 and 2.72 kg, respectively) with correlations that were statistically significant for the single frequency approach but not for the multi-frequency approach (r=0.71, P<0.01 and r=0.45, ns, respectively). The high prediction errors render these impedance techniques inappropriate, at the present time, for monitoring total water changes in individual intensive care patients.
Asia Pac J Clin Nutr. 1995;4(1):125-128.doi:
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The significance of sarcopenia in relation to health
Author:Roche AF
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Abstract:Sarcopenia is a lack of skeletal muscle. Knowledge of this condition is incomplete because an accurate method for the measurement of total muscle mass is lacking. In the absence of such a method, regional measurements are used commonly. When these are based on anthropometry, the values are inaccurate, but they are important because of their relationships to risk factors for some diseases and because large amounts of data are available. It is suggested that low values for the body mass index IBMI) indicate low values for fat-free mass (FFM) of which muscle is known to be a major constituent. Furthermore, low values for the BMI and the circumferences or areas of arm muscle are associated with increased mortality rates.
Asia Pac J Clin Nutr. 1995;4(1):129-132.doi:
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Causes of inadequate protein-energy status in thalassemic children
Author:Tanphaichitr VS, Visuthi B, Tanphaichitr V
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Abstract:Height-for-age, weight-for-age, triceps skinfold thickness (TST), mid upper arm circumference (MUAC), and mid upper arm muscle circumference (UAMC) were determined in 47 thalassemic children, ages ranging from 4- 5 years. Their mean (± SEM) height-for-age, weight-for age, TST, MUAC, and UAMC were 90.51± 0.98, 79.91± 2.33, 88.01± 1.26, 83.02± 1.37 and 80.09± 1.59% of standard values. Based on height-forage of less than 95% of standard values and weight-for-age, TST, MUAC, and UAMC of less than 90% of standard values, the prevalences of protein-energy malnutrition (PEM) in these thalassemic children were 72.3,74.5,53.7,75.6 and 82.9%, respectively. The causes of their inadequate protein-energy status were due to: (a) chronic hypoxia evidenced by the significantly positive correlations between haemoglobin levels and height-for-age (r=0.65, P<0.001), weight-for-age (r=0.58, P<0.001), MUAC (r=0.67, P<0.001) and UAMC (r=0.63, P<0.001); (b) zinc deficiency evidenced by significantly positive correlations between plasma zinc levels and height-for-age (r=0.26, P<0.05), MUAC (r=0.41, P<0.005), and UAMC (r=0.41, P<0.005) and significantly negative correlation between urinary zinc levels and UAMC (r=0.34, P<0.02); and (c) low energy intake, ie 65% of the mean recommended energy intake.
Asia Pac J Clin Nutr. 1995;4(1):133-135.doi:
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Body mass index and nutritional status: the effect of adjusting body mass index for the relative sitting height on estimates of the prevalence of chronic energy deficiency, overweight and obesity
Author:Norgan NG
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Abstract:Low body mass index (BMI) has been proposed as a practical measure of adult chronic energy deficiency (CED), although it was well-known limitations. One of these is that its interpretation is complicated by the influence of body proportions, in particular the relative leg length. This has been quantified by examining data collected before 1970 of 349 adult Australian Aborigines following a largely traditional way of life. These Australian Aborigines exhibited low sitting height: stature ratios (SH/S), 0.48± 0.02, (mean ± sd), range 0.41-0.54, ie they are relatively long legged, and low BMI, 19.9± 3.2, range 12-30 kg/m2. Thirty percent of individuals had BMI less than 18.5 kg/m2, a suggested cut-off for CED. The regression of BMI on SH/S was determined in men and women separately but found by covariance analysis not to be different and a common equation for both sexes was calculated. When BMIs were standardized to a SH/S of 0.52, a value found in Europeans and other Indo-Mediterraneans, the percentage classed as chronically energy-deficient fell to 7%. In Asians and indigenous Americans with their high SH/S, the percentage of the population with overweight and obesity could be overestimated and the extent of CED underestimated. In populations with a mean SH/S of 0.52, such as Europeans and Pacific peoples, standardizing SH/S to 0.52 would not effect the prevalence of CED or overweight and obesity but could move individuals across diagnostic boundaries as there is variability in SH/S in all population groups. In conclusion, when using BMI to assess energy nutritional status single cut-offs are not applicable to all individuals and population groups without allowance for the body form and type.
Asia Pac J Clin Nutr. 1995;4(1):137-139.doi:
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The body cell mass and altered protein energy metabolism in cystic fibrosis
Author:Thomson M, Bucolo S, Thomas B, Holt T, Shepherd R
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Abstract:To further investigate the body cell mass (BCM) in CF, as the central metabolically active body compartment, and to determine if measures used as reference standards after comparative differences in protein energy metabolism, BCM was measured by K40 analysis (n= 144 CF, 69 M, 71 F, ages 0.3-17 years) related to age and gender control date (n=1478). Protein synthesis was studied by whole body C13 leucine kinetics (LSYN, n=10 well nourished vs 7 undernourished CFs matched for Ht, Sex and FEV1). Energy expenditure (REE) was studied by indirect calorimetry (n=4 Δ F508 CF infants with no lung disease vs n=12 age, wt, ht and sex matched healthy infants). BCM was <1 sd below 50th centile in 75% of CFs although only 15 and l0% had weights or heights <1 sd below 50th centile. Mean LSYN and REE did not significantly differ between groups in absolute values or corrected for weight, height or surface area, but were accelerated (P<0.01) when corrected for BCM.
Asia Pac J Clin Nutr. 1995;4(1):141-142.doi:
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Hormones, body composition and cardiovascular risk
Author:Sjöström L, Alpsten M, Andersson B, Bengtsson BÅ,
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Abstract:Some 20 compartments of the body may be measured by CT and organ areas determined in 28 CT scans. Advantages of CT are described. While there have been extensive studies of hormones in pre- and postnatal growth, apart from evidence from disease, the role of hormones in adults has been less known. Data on growth hormone and sex hormones, from organ-oriented body composition studies, are summarized, together with implications for the relation between body composition and cardiovascular risk. Sex-specific anthropometric equations allow estimation of LBM, visceral and sc AT with <20% error. In the obese such estimates show visceral AT to be a stronger risk predictor than other compartments or W/HR.
Asia Pac J Clin Nutr. 1995;4(1):143-149.doi:
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The effects of growth hormone on body composition
Author:Brummer RJ, Bengtsson BÅ
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Abstract:The action of growth hormone (GH) on longitudinal bone growth is well known and easily recognized. GH also has profound effects on body composition. Generally, GH increases the amount of body cell mass and extracellular water and decreases body fat. The lipolytic effect of GH was demonstrated in the 1930s when it was shown that pituitary extracts reduced body fat in rats. Recently, GH treatment has been shown to promote a redistribution of adipose tissue from the abdominal (android) to a more peripheral (gynoid) distribution. The reverse change has been demonstrated in patients with acromegaly after successful treatment. The anabolic action of GH was first demonstrated when nitrogen retention was observed after GH administration. GH seems to stimulate cell division and increase the amount of DNA in the muscle. In patients with acromegaly the overweight is partly explained by a significant increase in body cell mass and muscle volume, compared to matched controls, demonstrated by several independent methods of determining body composition. In GH-deficient patients, however, the overweight is due to an increase in adipose tissue mass and the body cell mass seems only decreased in subjects below the age of 55. The anabolic action of GH is accompanied by sodium and fluid retention, due to increased sodium pump activity. In acromegalic subjects extracellular water has been shown to be increased by up to 25%. However, in GH-deficient adults the extracellular fluid volume is markedly decreased by approximately 15%. Replacement therapy with recombinant human GH in patients with GH deficiency restores the extracellular fluid volume by an initial rapid expansion of the fluid volume, followed by a slight decrease towards a new steady-state level. GH has profound effects on body composition. Although body composition is determined by many factors including age and physical activity, changes in body composition can be helpful parameters in following the effect of GH in various body compartments.
Asia Pac J Clin Nutr. 1995;4(1):151-155.doi:
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Future technologies
Author:Thomas BJ
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Abstract:Research and development in the area of body composition has undergone considerable changes in the last decade. These changes have resulted in part from the improvement of established techniques-but also from the introduction of methods based upon principles new to body composition studies. One can observe in recent developments a trend towards less invasive techniques, and cheaper, more portable instrumentation. There has also been a move towards improving the efficacy of the information obtained. The trend towards less invasive techniques, which includes lower dose, is particularly important when considering applications involving children. The question of 'future technologies' needs to be considered against the background of these developments if one is to propose the direction of future research. This paper considers possible new and modified technologies which may find application in the measurement of body composition. In addition, currently emerging technologies which need further research and development will be discussed. Examples of technologies examined in this paper include: •a possible new approach to measurement of bone mineral density in neonates using laser beam transmission, •possible modification of dual-energy X-ray absorption (DEXA) techniques for improved precision in the measurement of the relative lean/fat component, and •the research required to validate the use of multifrequency bio-electrical impedance analysis for measurement of extracellular and total body water.
Asia Pac J Clin Nutr. 1995;4(1):157-159.doi:
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Quality control in body composition measurements
Author:Stroud DB, Borovnicar DJ, Xiong DW
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Abstract:The principles of quality control (QC) are not new; they have always been with mankind. At the most fundamental level QC can be defined as a state of mind in which we continually strive to analyse what we are doing in order to produce a 'product' which our peers will judge to be 'better' . Paradoxically, this simple concept is expressed in many different ways within the multi-disciplinary team that makes up a body composition laboratory and very careful discussion is needed to ensure uniformity of technique and results. The situation is made even more difficult by the large range of equipment and techniques that are now available for the measurement of body composition. It is necessary to have a detailed understanding of the equipment and techniques and to have good communication within the group of workers. Good communication is essential to ensure that all members of the group have a clear understanding of the relevant guidelines and principles of QC and measurements, and to ensure that they are applied consistently throughout all the work of the laboratory. A detailed understanding of the equipment is necessary in order to define and implement simple tests that will monitor the most sensitive or troublesome features without imposing an undue burden upon the operator. There is a need for such tests to be automated as much as possible and, in general, there is a need for a more professional approach to the analysis of error and its propagation throughout an experiment. Inter comparisons of results between centres is a logical, but generally difficult requirement and some of the problems that arise would be simplified if equipment designs were more standardized. Finally, all these requirements need to be achieved within an environment that is continually changing with respect to the aims of the laboratory and the funding bodies.
Asia Pac J Clin Nutr. 1995;4(1):161-165.doi:
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Body composition by dual-energy X-ray absorptiometry-a review of the technology
Author:Nord RH, Payne RK
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Abstract:This paper begins with a fundamental description of the dual-energy X-ray absorptiometry (DXA) technique for measurement of bone mineral. It describes how, in extending the technique to do accurate assessment of body fat and lean, it is important that material standards for fat and lean exist, and that a suitable model for fat distribution in the body be developed. The computational steps employed in DXA and in the familiar underwater weighing (UWW) technique are compared and contrasted. Experimental data on over 350 human subjects shows that the percent fat results of DXA and UWW do not agree. However when both methods are used to determine body tissue density, there is good agreement. The authors suggest that the discrepancy may lie with the equations that are used in UWW to compute % fat from body density.
Asia Pac J Clin Nutr. 1995;4(1):167-171.doi:
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Dual-energy X-ray absorptiometry vs underwater weighing comparison of strengths and weaknesses
Author:Nord RH, Rayne RK
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Abstract:This paper discusses a number of strengths and weaknesses of two methods for determination of body fat, Dual-energy X-ray Absorptiometry (DXA) and underwater weighing (UWW). Several error sources are theoretically quantified. One source of error in the UWW method, variation in bone mass fraction, is examined using data gathered on 219 human subjects who were measured by both methods. The experimental data show the expected linear form but do not exactly match the theoretical curves, indicating that all error sources are not completely understood. The data suggest a possible error in the Brozek equation which is commonly used to compute % fat in UWW.
Asia Pac J Clin Nutr. 1995;4(1):173-175.doi:
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A new equation set for converting body density to percent body fat
Author:Nord RH, Rayne RK
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Abstract:One source of error in the underwater weighing (UWW) method of body fat determination is variability in bone mass as a fraction of total nonfat mass. We examined this error theoretically and experimentally using data gathered on 219 human subjects who were measured by UWW and also by the newer technique of dualenergy X-ray absorptiometry (DXA). The experimental data suggest an error was made in the assumed bone mass fraction used in the derivation of the Brozek equation, the standard means of converting the body density values obtained in UWW to body fat percent. Using this new experimental data, a new equation (set) is proposed for use in UWW measurements.
Asia Pac J Clin Nutr. 1995;4(1):177-179.doi:
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The value and limitation of dual-energy X-ray absorptiometry
Author:Harrison JE, Muller C, Krishnan SS, Kooh SW, Norie
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Abstract:In population studies, in which patients and controls are of comparable size, bone mineral area density (BMD) gives reliable results for mean bone mass data although, with sequential data, BMD may under-estimate the degree of change in bone mass. In children BMD data should be reliable, provided that patients and controls, matched for age and sex, are also of the same size. With disease children may be small for their age so that low bone mass by BMD may be due to small body size and not necessarily to osteopoenia. In these situations the bone mineral content (BMC) index may be more reliable than BMD. To assess bone mass status in individuals, BMC index, as well as BMD, should be used, particularly with adults at the extremes of body size (the very small or very tall).
Asia Pac J Clin Nutr. 1995;4(1):181-182.doi:
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Fat-free mass from dual-energy X-ray absorptiometry and from other procedures
Author:Roche AF, Guo S, Wellens R, Chumlea WC, Wu X, Sier
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Abstract:Fat-free mass (FFM) values were obtained for 99 males and 114 females (8-68 years) who are participants in the Fels Longitudinal Study. These participants were assessed by dual-energy X-ray absorptiometry (DEXA) and by densitometry using (i) a multi-component model including measures of total body water (TBW) and total body mineral (Fels), (ii) a model with age- and sex-specific values for the density of FFM (Lohman), and (iii), a 2-component model (Siri). In males <25 years, the mean DEXA and Siri values were similar, but both were significantly smaller than the Lohman and Fels means. In females <25years, the mean DEXA values are smaller than those from the other methods. In men aged 25-54 years, the mean DEXA and Fels means showed good correspondence, but the Lohman and Siri means were significantly smaller. In women aged 25-54 years, the DEXA means were considerably smaller than those from the Siri, Lohman and Fels models. At ages >54 years, the findings are tentative because of the small sample sizes but they indicate that the DEXA and Fels means are similar in men and that both are larger than the Lohman and Siri means. In women aged >54 years, the DEXA, Siri and Lohman means are similar, but they are smaller than the Fels means. In another overlapping group (50 men; 78 women; 18-67 years), FFM was obtained from TBW and from the Siri method. The technical errors for TBW-Siri comparisons were 1.7 kg (men) and 1.8 kg (women) with large coefficients of reliability (87%, men; 90% women). It was concluded that DEXA estimates of FFM are not interchangeable with those from the other methods tested. These findings are relevant to the selection of methods for the measurement of body composition and the interpretation of the literature.
Asia Pac J Clin Nutr. 1995;4(1):183-185.doi:
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Whole body measurement of C, N and O using 14 MeV neutrons and the associated particle time-of-flight technique
Author:Mitra S, Wolff JE, Garrett R, Peters CW
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Abstract:Our aim has been to construct a portable prototype instrument for measuring the whole body composition in vivo of growing lambs in terms of fat. protein and water by determining the mass of carbon, nitrogen and oxygen present. A small and compact sealed tube neutron generator which has the capability of exploiting the associated particle time-of-flight technique has been used for prompt gamma 14 MeV neutron activation analysis of C, N and O. This technique allows only gamma rays generated by neutron reactions within a defined volume to be recorded and offers a superior signal-to-noise ratio over existing prompt gamma neutron activation techniques. Based on the results obtained from irradiating a 41.4 kg meat phantom, we anticipate that an instrument comprising the neutron generator and four 15 x 15 x 45 cm Nal(TI) gamma ray detectors can be assembled to determine in vivo, protein, fat and water with precisions of 4.1, 5.4 and 1.2% (CV), respectively, within a 15 min scan. The radiation dose delivered would be ~0.03 mSv.
Asia Pac J Clin Nutr. 1995;4(1):187-189.doi:
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Errors in determination of total body protein by in vivo neutron activation of nitrogen due to non-uniform neutron fluence inside the patient
Author:Tölli J, Larsson L, Alpsten M
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Abstract:Total body protein can be estimated by in vivo neutron activation of nitrogen. The method is based on capture of thermal neutrons in a 14N(n,g )15N reaction. Sources of error associated with this method, such as background subtraction, variations in detection efficiency, etc, are analysed. Different neutron reactions (absorption, elastic and inelastic scattering) cause the neutron fluence to decrease inside the body. The activation profile through the body is non-uniform which causes errors in the calculation of total body nitrogen. A reduction of nitrogen by 5% in a 3 cm thick volume near the body surface would result in an error in the determination of total body nitrogen of approximately 0.3%. The error induced by changes in thickness of the subcutaneous fat has also been estimated and the results show that a 5 mm change in subcutaneous fat thickness changes the count rate from nitrogen by 5%.
Asia Pac J Clin Nutr. 1995;4(1):191-194.doi:
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Problems associated with using in vivo proton (1H) magnetic resonance spectroscopy to quantify liver fat
Author:Marks SJ, Dixon RM, Styles P, Ryley NG, Hockaday T
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Abstract:In-vivo 1H magnetic resonance (MR) spectra of the liver were obtained in 8 patients admitted for liver biopsy. These patients had abnormal liver function and the presumptive diagnosis of fatty liver prior to biopsy. Two patients with NIDDM were also studied but liver biopsies were not performed as liver function was normal. The MR spectra, obtained on a 60 cm clear-bore 1.9 tesla superconducting magnet showed two 1H resonances, one from water and the other from repeating methylene protons - (CH2)n - in triglyceride. The lipid: water signal ratio was used to characterize tissues as subcutaneous fat (high lipid:water ratio), normal liver (low lipid: water ratio) and fatty liver (intermediate lipid: water ratio). The spectra obtained at the greatest depth from the probe surface ~4.5 cm) was used as it was most likely to represent liver tissue. Although all 8 patients were expected to have fatty liver only 2 had evidence of significant fatty changes on microscopy. This was assessed by counting the vacuoles of fat over the area of the biopsy specimen and quantitated as 'fat vacuoles per high power field' (f/hpf). In the 2 patients with NIDDM, unusual stack plots suggested technical difficulties with 1H MR spectroscopy for in-vivo assessment of fatty liver. The first patient, PT had a significant increase in lipid:water ratio on the spectra thought to represent liver (lipid:water ~ 65% cf levels <3% in norma liver and 12.6% + 26.5% in those patients subsequently found to have fat on biopsy). This was later found on MR imaging to represent omental fat lying between the liver and muscle layer. The second patient, OM had a large amount of subcutaneous fat overlying the area assessed. As seen on the stack plot, the probe depth was not great enough to pass through the subcutaneous fat and muscle layer to penetrate liver tissue. There was a significant correlation between the lipid:water signal ratio and visible fat on biopsy in those patients who underwent liver biopsy. Difficulties experienced with probe depth suggests imaging would be necessary prior to spectroscopy to ensure liver tissue is actually assessed.
Asia Pac J Clin Nutr. 1995;4(1):195-198.doi:
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High frequency energy absorption and the measurement of limb muscle
Author:Roche AF, Wellens R, Guo S, Siervogel RM, Boska MD
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Abstract:High frequency energy absorption (HFEA) is being developed as a portable, inexpensive, non-invasive procedure for the measurement of muscle mass within cross-sections of limbs. The instrument consists of a flexible coil 2.5 cm wide of which the length can be adjusted over a 10 cm range. A series of coils of different lengths has been constructed that are jointly suitable for limbs with circumferences ranging from 20 to 75 cm. To measure HFEA, a coil of appropriate length is attached to a 9v battery that, through an oscillator, produces a frequency varying from 15 MHz (longest coil) to 40 MHz (shortest coil). Zero readings, with the coil set at the same circumference as the limb, are obtained before and after HFEA is measured and they are used to adjust the observed values. HFEA, in theory, is related to the number of electrolytes deep to the coil and almost all these electrolytes are in muscle. Good precision has been demonstrated and the instrument has been successfully validated against saline solutions. A previous model was validated against magnetic resonance images with good results (r2 about 0.8). Further validation of the present model against magnetic resonance images is almost complete; these findings are presented.
Asia Pac J Clin Nutr. 1995;4(1):199-201.doi:
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