PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Body Composition”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 505 records · Page 28Linked to original sources

Differences in body-composition assumptions across ethnic groups: practical consequences.

Body-composition methodologies rely on assumptions that are not constant across ethnic groups. The consequence is that the methods used need to be population specific to guarantee unbiased conclusions. Alternatively, assumption-free methods such as chemical multiple-compartment models or scanning techniques should be used. Adequate and unbiased scientific data on body fat among ethnic population groups are necessary for a better understanding of the aetiology of obesity and its co-morbidities. The World Health Organization cut-off points for underweight, overweight, obesity and fat distribution, now universally defined, may need revision because the relationship between body mass index and body composition, and between indices of fat distribution and the actual amount of visceral fat, differ across ethnic groups. The need for ethnically specific cut-off points for obesity and fat distribution is substantiated, for example, by elevated disease risks at low levels of body mass index in several populations. Properly designed and conducted studies are needed to obtain unbiased information on these topics.

Adipose Tissue↗

Leptin, body composition and bone mineral density in premenopausal women.

Body weight is known to be associated with bone mass, however, it is unclear whether body composition, as reflected by the percent of total weight that is fat tissue (%fat), is associated with bone mass independently of weight. Fat tissue is metabolically active, and hormonal factors may mediate an association of %fat with bone mass. Leptin, a hormone produced in fat tissue, has recently been shown to be inversely related to bone mass in mice, but whether it is related to human bone mass is uncertain. We sought to investigate the associations of %fat and of serum leptin concentration with bone mineral density (BMD) in a cohort of 153 premenopausal women. BMD measurements of the total hip, lumbar spine and total body as well as body composition were measured by dual energy X-ray absorptiometry (DXA). Serum leptin levels were established using a commercial competitive binding assay. Individually, body weight, %fat and leptin were each positively associated with BMD at all three sites. However, when we examined BMD either as a function of both body weight and %fat together, or as a function of both body weight and leptin together, we found that for a given body weight, BMD appeared to be inversely associated with %fat and similarly appeared to be inversely associated with leptin. When BMD was examined as a function of %fat and leptin together, we found that for a given %fat, leptin appeared to be inversely associated with BMD. In summary, the results of this study suggest that for a given body weight, a higher proportion of fat and a higher serum leptin concentration have negative associations with bone mass in premenopausal women.

Absorptiometry, Photon↗

A new method for estimation of body composition in the live rat.

Measurement of total body electrical conductivity (TOBEC) has been used to estimate lean and fat content of meat based on the principle that electrical conductivity of lean tissue is far greater than that of fat. This approach was used to estimate body composition of live rats. An instrument designed for commercial analysis of ground meat (DjMe 100) was used to measure TOBEC in 30 male Sprague-Dawley rats (197-433 g). Individual TOBEC values were obtained in 20 seconds and repeated twice for each rat. The animals were then killed with ether, hair was shaved, lungs collapsed and body density measured hydrostatically. Carcasses were homogenized and analyzed for fat, nitrogen, and water. A high correlation was found between TOBEC and lean body mass by densitometry (r = .97) and between TOBEC and fat-free mass derived from direct carcass analysis (r = .97). Rats weighing up to 450 g could be accommodated in this particular instrument. Measurement of TOBEC should prove useful in estimating body composition and monitoring its changes in live rats and other small laboratory animals.

Animals↗

Sexual dimorphism in body composition, weight status and growth in prepubertal school chiildren from rural areas of eastern Austria.

Sexual dimorphism in stature, weight status and body composition were analyzed in a sample of 398 prepubertal children (213 girls, 185 boys) ageing between 7 and 10. Furthermore the prevalence of overweight was tested. Body composition parameters were determined using TBF 105 Body composition analyzer according to BIA-method. Highly significant sex differences in body composition were observed (p < 0.001). In contrast, stature, weight and BMI showed no significant differences between the two sexes. Nevertheless, a significant higher portion (p < 0.05) of girls (29%) corresponded to the definition overweight according to ASNS (Austrian Survey of Nutritional Status), while only 20% of the boys felt into the category overweight. The results of the present study showed not only significant sex differences in body composition, especially in fat mass, long before puberty onset, but also a significantly higher prevalence of overweight among prepubertal girls in comparison to prepubertal boys.

Adipose Tissue↗

Body composition during the first year of life.

Knowledge of changes in body composition is of great potential benefit to the understanding of the nutritional needs and functional outcome of nutritional management for both healthy and sick infants. This review evaluates the different methods presently available to evaluate whole-body composition analysis based on different models, i.e. 2, 3, or more compartments. Analysis of the various approaches related to age, body weight and body length suggests that the major differences observed between the techniques could be preferentially related to differences in the population and that gender is one of the major determinants of whole-body composition during the first year of life. Among the techniques dual-energy X-ray absorptiometry (DEXA) and, more recently, air displacement plethysmography appear to be major techniques that have been evaluated in infants. Determination of weight gain composition is one of the major keys to the evaluation of the nutritional requirements, whereas the dynamic aspect during the first years of life could play a fundamental role in the nutritional programming of adult morbidity. Recent data suggest that protein intake and the protein:energy ratio are the main determinants of weight gain composition in preterm infants. Nevertheless, these data need to be confirmed in larger cohorts evaluated during the first year of life. To that, DEXA appears to be a useful technique to obtain sequential analysis of weight gain composition over a longer period of time and in a less invasive fashion.

Body Composition↗

Body composition in acromegaly: the effect of treatment.

Total body water (TBW) and total potassium (TBK) were measured in patients participating in a follow-up investigation of all acromegalic patients seen between 1956 and 1984. The results were compared with population-based estimates of TBK and TBW calculated from height (BH), weight (BW) age and sex, using data from a large number of healthy subjects (n = 476). The findings were compared with values obtained at diagnosis and were also related to growth hormone (GH) and IGF-I/SmC concentrations at follow-up. BW at follow-up was unchanged compared to BW at diagnosis and was 9.7 and 10.0 kg higher in males and females, respectively, than in healthy subjects of the same BH (BWnorm). Growth hormone concentration at follow-up correlated directly with excess extracellular fluid volume (ECW%) (P less than 0.001) and inversely with the ratio observed/predicted body fat (BF%) (P less than 0.001) as well as with BW/BWnorm (P less than 0.05). On the other hand, GH concentration did not correlate with excess body cell mass (BCM%) estimated from TBK. IGF-I/SmC concentration correlated with GH concentration at follow-up (P less than 0.001) and with ECW% (P less than 0.01) but not with BCM% or BF%. In 39 patients, data on body composition were also available at diagnosis. Of these, three males had developed gonadal insufficiency and their BCM had decreased markedly. One patient had suffered from hemiplegia. Five patients had not received any treatment. In the remaining 30 treated patients, those with a post-treatment GH concentration below 5 mU/l were normalized with respect to ECW and BF. BCM, however, was unchanged. In contrast, patients with GH concentration greater than or equal to mU/l displayed unchanged body composition. Furthermore, BH decreased significantly in successfully treated patients.

Acromegaly↗

Effects of growth hormone replacement on physical performance and body composition in GH deficient adults.

OBJECTIVES: Adults with GH deficiency complain frequently of low energy levels resulting in a low perceived quality of life. Body composition is altered, with increased fat mass and decreased lean body mass, and muscle strength is reduced. The aims of this study were to determine the effects of GH replacement on physical performance and body composition in GH deficient (GHD) adults. STUDY DESIGN: The study consisted of a 6-month randomised, double-blind, placebo controlled study of the administration of GH (0.25 IU/Kg/week (0.125 IU/kg/week for the first four weeks)) followed by a 6-month open phase of GH therapy. PATIENTS: Thirty-five GHD adults (17F), mean age 39.8 years (range 21.1-59.9), on conventional replacement therapy as required. METHODS: Maximum aerobic capacity was measured using an incremental walking test to volitional exhaustion on a motorized treadmill. Quadriceps muscle strength was assessed by measuring maximum voluntary contractions and body composition by dual energy X-ray absorptiometry (DEXA). RESULTS: There were no statistically significant changes in quadriceps muscle strength between the GH and placebo groups. In both groups, there was a significant increase in quadriceps muscle strength compared to baseline during the double-blind period (GH group: P = 0.016; placebo group: P = 0.048). Compared to baseline, muscle strength was further improved in the GH treatment group after 12 months of treatment (P = 0.007). No further improvement was noted in the placebo group after 6 months on open GH treatment. In the placebo group, maximum aerobic capacity decreased during the placebo period (P = 0.017). No significant change was observed in the GH group. During open GH treatment the previously placebo treated group had a significant increase of maximum aerobic capacity (P < 0.049) whereas no significant improvement could be seen in the GH group. In the GH group there was a significant increase in lean body mass (P = 0.001) and a significant decrease in fat mass (P < 0.001). No statistically significant changes were noted in the placebo group: the differences in these changes between treatment groups were statistically significant (lean body mass: P = 0.009; fat mass: P < 0.001). The changes in body composition in the GH group during the 6 month placebo-controlled period were maintained during continued open treatment. Similar changes in body composition to those observed in the GH group during the 6 month placebo-controlled period were also seen in the placebo group once the patients received GH treatment. CONCLUSIONS: Our data show that GH replacement in GH deficient adults is associated with favourable changes in body composition, which could be important in the long term health outcome and physical activity of GH deficient patients. Our data support the concept that GH therapy alone, in the absence of some form of exercise programme, may increase the amount of lean tissue but not the quality or functional capacity of this tissue and it may be that training, in addition to GH therapy, may be necessary to significantly increase physical performance in these patients. We suggest that future trials with GH therapy and general approaches to the treatment of GH deficiency should include a planned activity programme as an approach to health improvement in these patients.

Absorptiometry, Photon↗

Benefits of exercise and dietary measures to optimize shifts in body composition with age.

Ageing is associated with changes in body composition, including an increase and redistribution of adipose tissue and a decrease in muscle and bone mass, beginning as early as the fourth decade of life. These changes have significant implications for the health and functioning of the individual because of their associations with chronic disease expression and severity, as well as geriatric syndromes such as mobility impairment, falls, frailty and functional decline. Therefore, understanding the preventive and therapeutic options for optimizing body composition in old age is central to the care of patients in mid-life and beyond. Pharmacological interventions are currently available for maintaining or improving bone mass, and much current interest is focused on anabolic agents that will preserve or restore muscle mass, as well as those that can potentially limit adipose tissue deposition. However, in this brief review, non-pharmacological modulation of body composition through appropriate dietary intake and physical activity patterns, will be discussed. There is sufficient evidence currently to suggest that a substantial portion of what have been considered 'age-related' changes in muscle, fat and bone are in fact related either to excess energy consumption, decreased energy expenditure in physical activity, or both factors in combination. In addition, selective underconsumption of certain macro- or micronutrients contributes to losses of muscle and bone mass. Each of the three compartments will be considered in turn, with recommendations for optimizing the size of these body tissue stores in early adulthood, and minimizing undesirable changes typically seen in middle and old age.

Adipose Tissue↗

One- and two-year change in body composition as measured by DXA in a population-based cohort of older men and women.

Changing body composition has been suggested as a pathway to explain age-related functional decline. No data are available on the expected changes in body composition as measured by dual-energy X-ray absorptiometry (DXA) in a population-based cohort of older persons. Body composition data at baseline, 1-yr follow-up, and 2-yr follow-up was measured by DXA in 2,040 well-functioning black and white men and women aged 70-79 yr, participants of the Health, Aging, and Body Composition Study. After 2 yr, a small decline in total body mass was observed (men: -0.3%, women: -0.4%). Among men, fat-free mass and appendicular lean soft tissue mass (ALST) decreased by -1.1 and -0.8%, respectively, which was masked by a simultaneous increase in total fat mass (+2.0%). Among women, a decline in fat-free mass was observed after 2 yr only (-0.6%) with no change in ALST and body fat mass. After 2 yr, the decline in ALST was greater in blacks than whites. Change in total body mass was associated with change in ALST (r = +0.58 to +0.70; P < 0.0001). Among participants who lost total body mass, men lost relatively more ALST than women, and blacks lost relatively more ALST than whites. In conclusion, the mean change in body composition after a 1- to 2-yr follow-up was 1-2% with a high interindividual variability. Loss of ALST was greater in men compared with women, and greater in blacks compared with whites, suggesting that men and blacks may be more prone to muscle loss.

Absorptiometry, Photon↗

Evaluation of modified multicompartment models to calculate body composition in healthy males.

Body volume was measured by underwater weighing (UWW) or with a skinfold caliper; bone mineral by dual energy X-ray absorptiometry (DXA); and body water by bioelectrical impedance analysis (BIA) in 22 healthy males. The percentage of water and bone mineral in fat-free mass had a significant effect on the calculated amount of fat using a two-compartment model. A three-compartment model based on field-adapted methods (skinfold thickness + BIA) to calculate body fat, correlated significantly with a more complex four-compartment model (UWW + BIA + DXA) (r = 0.95, p < 0.001). The advantages of three- and four-compartment equations are that they reduce the number of assumptions.

Absorptiometry, Photon↗

Validity of body mass index compared with other body-composition screening indexes for the assessment of body fatness in children and adolescents.

BACKGROUND: Validation studies of height- and weight-based indexes of body fatness in children and adolescents have examined only small samples of school-age children. OBJECTIVE: The objective was to validate the performance of age- and sex-specific body mass index (BMI) compared with the Rohrer index (RI) and weight-for-height in screening for both underweight and overweight in children aged 2-19 y. DESIGN: Data from the third National Health and Nutrition Examination Survey (n = 11096) and a pooled data set from 3 studies that used dual-energy X-ray absorptiometry (n = 920) were examined. The receiver operating characteristic curve was used to characterize the sensitivity and specificity of these 3 indexes in classifying both underweight and overweight. Percentage body fat and total fat mass were determined by dual-energy X-ray absorptiometry. Subcutaneous fat was assessed on the basis of the average of triceps and subscapular skinfold thicknesses. RESULTS: For children aged 2-19 y, BMI-for-age was significantly better than were weight-for-height and RI-for-age in detecting overweight when average skinfold thicknesses were used as the standard, but no differences were found in detecting underweight. When percentage body fat or total fat mass was used as the standard, BMI-for-age was significantly better than was RI-for-age in detecting overweight in children aged 3-19 y. No differences were found between BMI-for-age and weight-for-height in detecting overweight or underweight. CONCLUSION: For children and adolescents aged 2-19 y, the performance of BMI-for-age is better than that of RI-for-age in predicting underweight and overweight but is similar to that of weight-for-height.

Absorptiometry, Photon↗

Body composition in acromegaly.

Total body water (TBW) and potassium (TBK) were measured in untreated acromegalic patients seen between 1956 and 1984 and the results were compared to values predicted from height (BH), weight (BW), age and sex, using data from a large number of healthy subjects (n = 476). Normal body weight for each patient (BWnorm) was predicted from BH and sex, the regression equations being derived from a representative population sample (n = 4017). The BH for each patient was compared with data on BH in 15,000 Swedes. The patients were significantly taller than the control population (P less than 0.001). In 107 (70%) of the 156 patients BH was above the median. Patients with an early onset of the disease were taller than those with a later onset. TBK and TBW were significantly higher than predicted from observed BW (P less than 0.001) and so was the quotient extracellular water (ECW)/intracellular water (ICW). Body fat (BF), on the other hand, was lower than predicted (P less than 0.001). Observed BW in male acromegalics was 8.1 kg higher than predicted from healthy subjects of the same BH (BWnorm), a difference explained by an average increase of 4.7 kg in body cell mass (BCM) (P less than 0.001) and 7.1 kg in extracellular water (P less than 0.001) simultaneously with a mean decrease of 3.7 kg in BF (P less than 0.01). Female acromegalics weighed on average 6.4 kg more than healthy women, a difference explained by an increase in BCM of 3.3 kg (P less than 0.001) and in ECW of 4.6 kg (P less than 0.001) concomitantly with a decrease in BF of 1.5 kg. Mean hGH concentration at diagnosis correlated inversely with the quotients observed/predicted BF (P less than 0.01) and BW/BWnorm (P less than 0.05) but not with the quotients observed/predicted TBK, TBW or ECW/ICW.

Acromegaly↗

Age-related variability in body composition methods for assessment of percent fat and fat-free mass in men aged 20-74 years.

INTRODUCTION: Assessing body composition is important because of the association between excess body fat or obesity and the increased risk for coronary artery disease, diabetes, hyperlipidaemia and hypertension. Methodological differences among indirect body composition techniques are a source of variability that can affect estimations of fat-free mass (FEM) or percent fat, especially for different age groups. PURPOSE: This study examined the effect of age on the estimation of body composition by three methods based on the two-component model. One hundred and fifty-three men were placed into 5-year age groups from 20-24 to 70-74 years. Body composition was assessed by hydrodensitometry (underwater weighing; 40K spectroscopy (K40) and anthropometry. RESULTS: Day-to-day reliability was excellent for each method. Correlation coefficients between methods, independent of age, ranged from r= 0.71 (K40 and UWW) to r = 0.83 (UWW and anthropometry) for% fat and from r = 0.76 (K40 and anthropometry) to r = 0.90 (UWW and anthropometry) for FFM. Correlations between techniques weakened and showed greater variability as age increased. UWW produced the highest % fat and lowest FFM for the different age groups, while K40 and anthropometry yielded similar body composition values. All three methods detected age-related differences in % fat; however, only UWW determined a significant age effect in FFM. The greatest discrepancies between the methods occurred for the oldest age groups (60-74 years), but noticeable differences began occurring after the age of 40. CONCLUSIONS: Each method produced reliable data. Care should be taken when choosing any method based on the two-component model, especially when different age groups are being examined, since estimating % fat and FFM is dependent on the age-related chemical composition of an individual and the limitations of each method.

Adiposity↗

Explaining body composition by some covariate factors among the elderly Bengalee Hindu women of Calcutta, India.

Understanding the changes in body composition with passage of time and factors associated with them will help to improve our knowledge and understanding about these processes and could guide in the prevention of functional limitations and formulation of better health care among the elderly. The present cross-sectional work was under taken to study the effect of age, menopause, age at first conception, educational level and physical activity in explaining body composition among 200 elderly (55 years and above) Bengalee Hindu women of Calcutta, India. Body composition measures namely percentage of body fat (PBF), fat mass index (FMI), and fat free mass index (FFMI) were calculated from skinfolds thickness using standard equations. Multiple regression analyses of body composition variables by covariate factors revealed that Age, age of onset of menopause, age at first conception, educational level and frequency of walking cumulative explains 35%, 28% and 21% of PBF, FMI and FFMI respectively. Present study revealed that beside age, both biosocial (age of onset of menopause, age at first conception, education level) and physical activity as measured by brisk walking have significant contribution in explaining body composition among elderly females. Significant negative impact of physical activity on PBF, FMI and positive impact on FFMI in the present study were also evident. Therefore, brisk walking could be useful to increase body's fat free mass.

Age Factors↗

Body composition in children on regular hemodialysis.

Body composition was estimated in 12 pubertal and 7 pre-pubertal children (age range 7-17 years) on regular hemodialysis for chronic renal failure (CRF). The results were expressed as a ratio of observed/predicted. Total body water (TBW) was normal and extracellular water (ECW) was significantly increased in both groups. Intracellular water (ICW), which reflects body cell mass, was significantly decreased in the pre-pubertal children but not in the pubertal children. The deviation in ICW from predicted normal was significantly more marked in the prepubertal children compared with pubertal children. Similarly, fat-free solids (FFS) were significantly decreased in the pre-pubertal, but normal in the pubertal children. Total body fat, estimated from body water, correlated significantly with skinfold thickness measurements and was normal in both groups, with the pre-pubertal children having significantly higher body fat ratio than pubertal children. Body fat was increased in some of the patients whose body cell mass was decreased. It is suggested that these changes are the result of a failure of normal energy metabolism with consequent body protein depletion, and that energy supplements as carbohydrate, particularly in the pre-pubertal patients, will increase body fat without affecting cell mass.

Adolescent↗

[Can the Body Mass Index and the waist:hips ratio (WHR) affect the correlation between impedance measurement and anthropometry in the evaluation of body composition?].

Among the numerous techniques used to measure body composition, this study utilised anthropometric methods (weight, height, circumference and skin folds) and impedance measurement (measurement of bioelectric impedance). Results from the two methods were compared in order to assess whether BMI parameters and the waist/hips ratio (WHR) influenced this correlation. One hundred and eighty patients (133 F, 47 M) were included in the study. Patients were divided into groups according to the degree of obesity expressed as BMI and WHR. Body composition was evaluated using anthropometric methods (according to Garrow Webster, Durnin-Womersley, modified Durnin-Womersley and Jackson-Pollock) and impedance measurement in which resistive bioelectric impedance is measured using a tetrapolar technique. A good correlation was generally observed in the female population between impedance assessment and anthropometric methods, and this correlation was not influenced by either BMI or WHR. In the male group, on the other hand, the correlation between the two methods was limited by BMI greater than 30 and WHR greater than 1. In conclusion, impedance measurement and plicometric methods are generally compatible, but areas of uncertainty arise in the male population with BMI greater than 30 and WHR greater than 1.

Adipose Tissue↗

Body composition studies in patients with wasting associated with tuberculosis.

OBJECTIVE: Wasting is a well-recognized manifestation of tuberculosis (TB), but little is known about the alterations in body composition that occur. Therefore, we measured regional and whole-body composition in patients with TB and wasting. METHODS: Body composition was measured by dual-energy x-ray absorptiometry in 18 patients with newly diagnosed TB and wasting (10 coinfected with human immunodeficiency virus [HIV]) and 22 controls (10 coinfected with HIV). RESULTS: Patients with TB and wasting had significantly lower body weight (48.6 versus 62.0 kg), lean body mass (39.6 versus 45.6 kg), and fat mass (6.2 versus 12.6 kg) than did controls. Patients with TB had significantly reduced lean tissue in the limbs (15.2 versus 19.1 kg) and trunk (21.3 versus 23.2 kg) and significantly higher trunk-to-limb lean ratio (1.41 versus 1.22) compared with controls. Patients with TB had significantly reduced fat in the limbs (3.4 versus 6.1 kg) and trunk (2.1 versus 5.7 kg) and significantly lower trunk-to-limb fat ratio (0.52 versus 0.92) compared with controls. Body composition measurements were no different in patients with and without HIV coinfection. CONCLUSIONS: Wasting in TB is associated with depletion of whole-body lean and fat tissue in approximately equal proportions overall, but lean tissue depletion is greater in the limbs and fat tissue depletion is greater in the trunk. HIV coinfection does not affect the magnitude or distribution of the body composition changes.

AIDS-Related Opportunistic Infections↗

Quantitative body composition analysis in awake mice and rats by magnetic resonance relaxometry.

OBJECTIVE: Magnetic resonance (MR) relaxometry has recently been introduced for noninvasive body composition analysis in awake mice. The purpose of the present study was to extend the method to rats and to introduce calibration procedures that render MR relaxometry fully quantitative. RESEARCH METHODS AND PROCEDURES: Proton T(2) MR relaxometry at 4.7 Tesla was used for body composition analyses in 700 awake mice and 400 rats of different strains and conditions. Relaxograms calculated from the signal decays observed with multi-spin-echo acquisition provided well-separated contributions of tissue water and fat. Analysis of fat composition was carried out in vivo using (13)C-MR spectroscopy. Evolution of body composition in rats was assessed during drug treatment. RESULTS: MR relaxometry for noninvasive body composition analysis in laboratory rodents was implemented on a standard MR scanner, and a throughput of >30 animals per hour was achieved. Excellent linearity and reproducibility with coefficients of variance as low as 2.5% and 1.7% were obtained in mice and rats, respectively. The lean mass-to-water ratio (mice, 1.35 +/- 0.03; rats, 1.39 +/- 0.04) and the proton density of fat (mice, 8.1 +/- 0.2; rats, 8.9 +/- 0.2 g/mol) were determined from cross-sectional data. Fat composition analysis by (13)C-MR spectroscopy corroborated these findings and yielded information on the average acyl chain length (16.3 +/- 1.6) and contributions of saturated (27 +/- 3%), monounsaturated (22 +/- 2%), and polyunsaturated (51 +/- 3%) fatty acids. Longitudinal assessments in rats treated with sibutramine and dexfenfluramine showed dose-related changes in body composition. DISCUSSION: T(2) MR relaxometry backed by solid calibration provides a powerful means for rapid quantitative body composition analysis in awake mice and rats that is suitable for serial investigations in pharmaceutical research.

Animals↗