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PubMed1997

Bioelectrical impedance assessment of body composition in thyroid disease.

To assess the metabolic effects of thyroid disease, body composition was determined by bioimpedance analysis (BIA) in 72 patients with untreated hyperthyroidism (mean age 48.7 +/- 1.9 years) and 26 patients with untreated hypothyroidism (63.8 +/- 3.4 years). Bioelectrical whole body resistance (R) and reactance (Xc) were used for computerized calculation of lean body mass (LBM), body cell mass (BCM), extracellular mass (ECM) and body fat (BF). Compared with age- and sex-matched healthy controls the most sensitive parameter indicating excess thyroid hormone was the ECM/BCM ratio which was markedly elevated in all hyperthyroid subjects. ECM/BCM alteration resulted from marked depletion of BCM with concomitant expansion of ECM. BCM change is thought to be predominantly due to a loss of muscle mass while ECM rise may reflect an increase in extracellular fluids. In contrast, hypothyroidism was characterized by an increase in BF besides a relatively unaffected LBM component. Serum parameters of thyroid function (tri-iodothyronine (T3), free thyroxine, TSH) did not correlate with the determinants of body composition except for a slight inverse relationship between the phase angle (Xc/Rx180 degrees/pi) and T3 concentration in Graves' disease patients. We conclude that hyperthyroidism is primarily accompanied by quantitative as well as qualitative changes in the lean body while considerable fat increase is the most important feature of hypothyroidism. Severity of body composition derangement cannot be predicted from the degree of thyroid dysfunction. BIA could become a useful tool which allows objective determination of even subtle metabolic manifestations of thyroid disease and should, therefore, complement conventional clinical and biochemical assessment.

Body Composition↗

PubMedDate not supplied

[Body composition changes in cancer: an experimental study].

With the aim to study body composition changes in tumor bearing rats submitted to different nutritional conditions, Wistar rats were separated in three diet groups: regular chow, aproteic diet and regular chow after three weeks of aproteic diet. Afterwards the animals were divided in two subgroups: Waler 256 carcinossarcoma bearing rats and tumor free controls. After the sacrifice body composition measurements by the carcass analysis method were performed. Tumor bearing rats presented significant waste of total body fat, body cell mass and increase of Na/K ratio without relation to the nutritional regimen. From this data we conclude that Walker 256 carcinosarcoma causes protein caloric malnutrition even in already depleted rats. After adequate refeeding, body composition rebuilding was obtained in tumor bearing malnourished rats.

Adipose Tissue↗

PubMed2006

No influence of body composition on serum growth hormone response to acute dynamic exercise.

Physical effort is a strong physiological stimulus that provokes an increase in blood growth hormone (GH) concentration. Interactions between GH and body composition are very complex. Seven athletes and seven age-matched controls completed a single 30-min bout of upright cycling exercise (5 % of VO(2max).) in order to estimate the influence of body composition on serum GH concentration during exercise. The serum GH concentration was measured in blood samples by standard immunoradiometric (IRMA) method. Anthropometric measurements were used for the calculation of body composition. There were no significant differences in total body mass or body mass index between the groups. The athletes had significantly less fat and higher bone and muscle mass. Serum GH concentration was 2.39 times higher in the athlets versus the control in the period of rest. During acute exercise, the serum GH concentration increased in both groups. No statistically significant differences between the groups in serum GH concentration were found either during the exercise or in the recovery. No correlation between body composition and serum GH concentration was found. Body composition depends on the level of physical activities but if the total body mass is in physiologycal range it does not influence the serum GH response to acute exercise.

Adult↗

PubMed2000

Changes in body composition of children with chronic renal failure on growth hormone.

Body composition is altered in children with chronic renal failure (CRF) and contributes to the significant growth failure seen in these children. Recombinant human growth hormone (rhGH) has been used in the past several years to improve the somatic growth of children with CRF. To determine if the growth achieved in these children occurs concomitantly with body compositional changes, seven prepubertal (n=6) and pubertal (n=1) children with chronic renal insufficiency (n=4) and end-stage renal disease (n=3) underwent measurements of total body fat (FM), fat free mass (FFM), bone mineral density (BMD), total bone mineral mass (TBBM), total body water (TBW), and total body potassium (TBK) before and 6 months after initiation of subcutaneous recombinant human growth hormone (rhGH) at 0.35 mg/kg per week. The techniques used included dual-energy X-ray absorptiometry (for measurement of FM, BMD, and TBBM), total body potassium counting (for measurement of TBK), and deuterated water for assessment of TBW. Significant increases in both height and weight were seen following 6 months of rhGH therapy. These increases were accompanied by significant reductions in FM (4.4+/-1.4 kg vs. 3.6+/-1.2 kg, P=0.002) and percentage fat (18.6+/-3.9% vs. 14.5+/-3.4%, P=0.04), while FFM (17.9+/-3.0 kg vs. 20.7+/-3.6 kg, P=0.04) increased significantly as did TBBM (776+/-171 g vs. 844+/-177 g, P=0.001). Increases in TBK, a measure of body cell mass, were also seen. No difference in total BMD was observed. Thus, growth in CRF is occurring with repletion of the FFM and TBBM compartments. Despite these improvements, no change was observed in the body mass index (BMI). Measurement of BMI alone does not define the compartmental catabolic losses in FFM.

Absorptiometry, Photon↗

PubMed2005

Postoperative changes in body composition after gastrectomy.

Nutritional status is one of the most important clinical determinants of outcome after gastrectomy. The aim of this study was to compare changes in the body composition of patients undergoing laparoscopy-assisted gastrectomy (LAG), distal gastrectomy (DG), or total gastrectomy (TG). Total body protein and fat mass were measured by performing a multifrequency bioelectrical impedance analysis using an inBody II machine (Biospace, Tokyo, Japan) in 108 patients (72 men, 36 women) who had undergone LAG (n=24), DG (n=39), or TG (n=45). Changes between the preoperative data and results obtained on postoperative day 14 and 6 months after surgery were then evaluated. The mean preoperative body weight of the subjects was 57.6+/-10.7 kg, the mean body mass index was 22.5+/-3.4 kg/m(2), and the mean fat % was 24%+/-7%. In the immediate postoperative period (14 days), the body weight loss in the LAG group was significantly lower than in the DG and TG groups (2.5+/-0.9 kg vs. 3.5+/-1.8 kg and 4.0+/-1.9 kg, respectively; P < 0.0001). The body composition studies demonstrated a loss of total body protein rather than fat mass. Six months after surgery, body weight was not significantly different from preoperative values in the LAG and DG groups (-1.2+/-3.8 kg and -1.8+/-4.7 kg, respectively), but had decreased by 8.9+/-4.9 kg in the TG group (P=0.0003). A body composition analysis revealed a loss of fat mass in the DG and TG groups. The patients who underwent gastrectomy lost body protein mass during the early postoperative period. The type and extent of surgery has an effect on long-term body mass and composition. Bioelectric impedance analysis can be used to assess body composition and may be useful for nutritional assessment in patients who have undergone gastrectomy.

Aged↗

PubMed1985

Estimation of human body composition by electrical impedance methods: a comparative study.

This study 1) further validated the relationship between total body electrical conductivity (TOBEC) and densitometrically determined lean body mass (LBMd) and 2) compared with existing body composition techniques (densitometry, total body water, total body potassium, and anthropometry) two new electrical methods for the estimation of LBM: TOBEC, a uniform current induction method, and bioelectrical impedance analysis (BIA), a localized current injection method. In a sample of 75 male and female subjects ranging from 4.9 to 54.9% body fat the correlation between LBMd and LBM predicted from TOBEC by use of a previously developed regression equation was extremely strong (r = 0.962), thus confirming the validity of the TOBEC method. LBM predicted from BIA by use of prediction equations provided with the instrument also correlated with LBMd (r = 0.912) but overestimated LBM compared with LBMd in obese subjects. However, no such systematic error was apparent when new prediction equations derived from this heterogeneous sample of subjects were applied. Thus the TOBEC and BIA methods, which are based on the differing electrical properties of lean tissue and fat and which are convenient, rapid, and safe, correlate well with more cumbersome human body composition techniques.

Adolescent↗

PubMed1998

Body mass and body composition after total thyroidectomy for benign goiters.

To date there are no data available as to whether postmenopausal women who undergo total thyroidectomy for benign euthyroid goiter demonstrate changes in body mass or body composition. We prospectively evaluated 8 postmenopausal women (mean age 57 +/- 7; range 48 to 70 years) who underwent total thyroidectomy for benign goiter. All patients were euthyroid preoperatively (serum free thyroxine [FT4] 12.7 +/- 0.6 pmol/L and serum thyrotropin [TSH] 0.98 +/- 0.2 mU/L) and were commenced on adequate thyroxine replacement immediately postoperatively in order to maintain a serum TSH within the normal range (0.5-4 mU/L). Body mass, body composition, and thyroid function were assessed preoperatively, and at 4 and 12 months postoperatively. Body composition was assessed by anthropometry and dual energy x-ray absorptiometry (Lunar DPX-L scanner). Eight healthy postmenopausal women without evidence of thyroid disease matched for age, weight, and estrogen therapy who were followed over the same period were used as controls. All patients were maintained in a euthyroid status throughout the study. No significant changes in body mass or any parameter of body composition were demonstrated at 4 and 12 months postoperatively. Similar findings were recorded in our control group. We conclude that total thyroidectomy in euthyroid postmenopausal women with benign goiter does not result in a significant change in either body mass or body composition if adequate thyroxine replacement is maintained.

Aged↗

PubMed2002

Validity of total and segmental impedance measurements for prediction of body composition across ethnic population groups.

OBJECTIVES: To test the impact of body build factors on the validity of impedance-based body composition predictions across (ethnic) population groups and to study the suitability of segmental impedance measurements. DESIGN: Cross-sectional observational study. SETTINGS: Ministry of Health and School of Physical Education, Nanyang Technological University, Singapore. SUBJECTS: A total of 291 female and male Chinese, Malays and Indian Singaporeans, aged 18-69, body mass index (BMI) 16.0-40.2 kg/ m2. METHODS: Anthropometric parameters were measured in addition to impedance (100 kHz) of the total body, arms and legs. Impedance indexes were calculated as height2/impedance. Arm length (span) and leg length (sitting height), wrist and knee width were measured from which body build indices were calculated. Total body water (TBW) was measured using deuterium oxide dilution. Extra cellular water (ECW) was measured using bromide dilution. Body fat percentage was determined using a chemical four-compartment model. RESULTS: The bias of TBW predicted from total body impedance index (bias: measured minus predicted TBW) was different among the three ethnic groups, TBW being significantly underestimated in Indians compared to Chinese and Malays. This bias was found to be dependent on body water distribution (ECW/TBW) and parameters of body build, mainly relative (to height) arm length. After correcting for differences in body water distribution and body build parameters the differences in bias across the ethnic groups disappeared. The impedance index using total body impedance was better correlated with TBW than the impedance index of arm or leg impedance, even after corrections for body build parameters. CONCLUSIONS: The study shows that ethnic-specific bias of impedance-based prediction formulas for body composition is due mainly to differences in body build among the ethnic groups. This means that the use of 'general' prediction equations across different (ethnic) population groups without prior testing of their validity should be avoided. Total body impedance has higher predictive value than segmental impedance.

Adolescent↗

PubMed1998

Body composition, energy expenditure, and energy intake in patients with Williams syndrome.

OBJECTIVE: To evaluate the body composition, resting energy expenditure (REE), and energy intake of adolescents and adults with Williams syndrome (WS) compared with matched healthy control subjects. METHODS: Body composition was determined by total body electrical conductivity and anthropometric measurements in six subjects with WS from the WS Clinic at Children's Hospital of Philadelphia and six healthy control subjects matched for age, height, and pubertal stage. REE was measured by open-circuit indirect calorimetry. Dietary intake was assessed by 3-day dietary records. RESULTS: Subjects with WS had similar anthropometric measurements to the control group except for a significantly lower percent body fat (17.1%+/-5.2% vs. 25.0%+/-6.7%). Dietary intake (measured in kilocalories per day) was similar between the two groups. REE was statistically higher by 155 kcal/day in the WS group after controlling for age, gender, and body composition. In addition, the WS group had a significantly higher percent predicted REE according to the World Health Organization equation, which adjusts for age, gender, and body weight. CONCLUSION: Adolescents and adults with WS have a similar dietary intake but a lower body fat than healthy control subjects. A higher REE may contribute to the thin body habitus and reduced total body fat stores of people with WS.

Adolescent↗

PubMed2003

Interactions between serum leptin, the insulin-like growth factor-I system, and sex, age, anthropometric and body composition variables in a healthy population randomly selected.

OBJECTIVE: Leptin secretion is influenced by many factors and the GH/IGF axis plays an important role in the regulation of body composition, but the physiological interactions between leptin and the IGF-I system remain unknown. In this study we investigated the relationship between leptin, the IGF-I system, and sex, age, anthropometric and body composition variables in a group of healthy adults randomly selected. DESIGN: A cross-sectional study. PATIENTS: The study included 268 subjects, representative of the whole population of the city of L'Hospitalet de Llobregat in sex and age distribution: 134 men aged 41.4 years, range 15-70 years; and 134 women, aged 40.7 years, range 15-70 years. MEASUREMENTS: Body mass index (BMI) was calculated, and body composition was determined by using a bioelectrical impedance analyser. Serum leptin concentrations were determined by using a radioimmunoassay (RIA). Serum total IGF-I concentrations, after acid-ethanol extraction, were also measured by RIA. Serum free IGF-I concentrations were determined by an enzymoimmunometric assay. Serum IGFBP3 concentrations were determined by RIA. Plasma basal TSH concentrations were determined by a specific electrochemiluminescence assay. RESULTS: In men the BMI was similar in all decades and waist/hip ratio increased in the last three decades. Fat-free mass decreased by decade. We observed an increase in leptin in the fourth decade with a decrease in IGF-I, free IGF-I and IGFBP3 throughout the decades. Basal TSH showed an increase in the last two decades. In women, BMI, waist/hip ratio and fat mass increased significantly in the last decades. Leptin concentrations increased in the last decades and total IGF-I, free IGF-I and IGFBP3 decreased by decade without changes in basal TSH concentration. In men, there was a positive correlation between leptin and BMI, waist/hip ratio, total body water, fat-free mass and fat mass, and these anthropometric and body composition variables showed a negative correlation with free IGF-I and IGFBP3, without any correlation with total IGF-I. In women, there was a positive correlation between leptin and BMI, waist/hip ratio, total body water, fat-free mass, and fat mass, which showed a negative correlation with total IGF-I and IGFBP3, without any correlation with free IGF-I. In men, total IGF-I was negatively correlated with waist/hip ratio without any correlation with the other variables and free IGF-I was negatively correlated with BMI and waist/hip ratio, and IGFBP3 did not show any correlation. In women, total IGF-I, free IGF-I and IGFBP3 were negatively correlated with BMI, waist/hip ratio and fat mass. The multiple linear regression analysis produced a model that explained 60.5% of leptin variability in men and 40% in women. Notably, only age, BMI, fat mass and waist/hip ratio brought an independent significant contribution to leptin variability. The final model also explained 28.2% and 60.4% of total IGF-I variability and 17.2% and 27.4% of free IGF-I variability in men and women, respectively. Age and leptin contributed to free IGF-I variability in men, and age and fat mass were significantly and independently associated with total IGF-I in women. CONCLUSIONS: In this well-characterized population of controls randomly selected without chronic disease or drug administration and with biochemically confirmed euthyroidism, we found that both men and women had a significant correlation between leptin levels and the IGF-I system, and anthropometric and body composition variables, but that leptin did not regulate the IGF-I system, and that the IGF-I system did not regulate leptin synthesis and secretion.

Adolescent↗

PubMed2002

Relations between frame size and body composition and bone mineral status.

BACKGROUND: Frame size is a description of the supportive structure of the skeleton that is used to adjust for skeletal mass and size in measures of body composition and weight. OBJECTIVE: Data from the Fels Longitudinal Study were used to investigate the relation between bicristal, elbow, knee, biacromial, and wrist breadths and measures of total body fat (TBF), fat-free mass (FFM), bone mineral content (BMC), and bone mineral density (BMD) from dual-energy X-ray absorptiometry. DESIGN: The sample consisted of cross-sectional data from 224 white men and 277 white women aged 23-65 y. Multiple regressions were conducted with stature-adjusted measures of body composition and bone mineral status as dependent variables and age and frame size as independent variables. RESULTS: Frame-size measures were significantly and positively associated with all body-composition and bone mineral measures in bivariate analyses. In both men and women, the significant models explained more of the variance in measures of TBF (R2 = 0.51 and 0.66, respectively) and FFM (R2 = 0.35 and 0.39, respectively) than in measures of BMC (R2 = 0.18 and 0.23, respectively) and BMD (R2 = 0.08 and 0.18, respectively). Bicristal, knee, and wrist breadths were associated with TBF, and biacromial, knee, and wrist breadths were positively associated with FFM. Biacromial breadth was positively associated with BMC and BMD. CONCLUSIONS: Frame size was more closely associated with TBF and FFM than with BMC and BMD. The association between frame size and body composition seems to be more structural than substantive. The relations between frame size and BMC and BMD are weak and apparently not related to body composition.

Absorptiometry, Photon↗

PubMed2006

Comparison of effects of gastric bypass and biliopancreatic diversion with duodenal switch on weight loss and body composition 1-2 years after surgery.

BACKGROUND: Gastric bypass (GB) is the most common surgical procedure for weight loss in the United States. Biliopancreatic diversion with duodenal switch (BPD/DS) is less routinely performed, perhaps because of its technical difficulty and metabolic concerns. The objective of this study was to determine whether these procedures had differential effects on weight loss and body composition. METHODS: Body composition was measured by bioimpedance (Tanita 310) at the initial consultation, and follow-up measurements were completed 1-2 years after surgery. RESULTS: Of the 72 patients in the study, 50, aged 46.2 +/- 8.5 years, had undergone GB and were measured 15.5 +/- 5.2 months after surgery and 22, aged 40.6 +/- 7.9 years, had undergone BPD/DS and were measured 19.5 +/- 7.5 months after surgery. Patient age and time after surgery were significantly different between the 2 groups. The body mass index (BMI) for the BPD/DS group was 53.6 +/- 11.9 kg/m(2), significantly greater than the BMI of the GB group (48.0 +/- 6.3 kg/m(2); P = .009). However, the percentage of body fat did not differ between the 2 groups (P = .515). Postoperatively, the BMIs for the GB group (31.5 +/- 5.0 kg/m(2)) and BPD/DS group (30.3 +/- 6.1 kg/m(2)) were not significantly different (P = .384). The percentage of body fat for the GB and BPD/DS groups had changed from 49.2% +/- 8.3% to 32.1% +/- 10.6% and 47.9% +/- 5.9% to 23.8% +/- 10.4%, respectively (P = .002). The BMI had decreased by 16.5 +/- 4.8 kg/m(2)after GB and 23.3 +/- 6.8 kg/m(2) after BPD/DS (P <.001). The decrease in fat was 17.1% +/- 8.2% after GB and 24.2% +/- 7.2% after BPD/DS (P <.001). CONCLUSION: The BPD/DS procedure is more effective in reducing the BMI and promoting fat loss than is GB. The assessment of the impact of these two operations on an individualized basis offers additional information to assist in the evaluation of these procedures.

Adipose Tissue↗

PubMed2000

Bone density, body composition, and inflammatory status in cystic fibrosis.

Low body weight and loss of bone mass are major problems in adults with cystic fibrosis (CF) and chronic pulmonary infection. Although these complications probably have a multifactorial origin, we hypothesized that the continuous acute-phase inflammatory and catabolic state may contribute. We determined body composition, bone turnover, physical activity, and circulating interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and their soluble receptors in 22 adults with CF and 22 age- and sex-matched healthy subjects. Comparisons were also made within patients before and after treatment of an exacerbation of respiratory symptoms. The patients had a lower mean (95% confidence interval [CI]) fat-free mass (FFM) 39.9 (36.3, 43.6) kg than healthy subjects, 49.4 (45.1, 53.7) kg, p < 0.05. The patients were in negative nitrogen balance and 20 had bone mineral density (BMD) Z scores </= 2.5 SD (n = 13) or </= 1 SD (n = 7) at least at one site. They had increased bone collagen breakdown, greatest in those with a reduced FFM. BMD was related to FEV(1) (r = 0.44), IL-6 (r = -0.60), and TNF-alpha-soluble receptors (r = -0.42, r = -0.50). Patients with a low FFM had greater concentrations of IL-6, which suppressed less after antibiotic treatment than in those with a normal FFM. Those with a low FFM were more catabolic and less active than those with a normal FFM. The association between altered body composition, catabolic status, and circulating inflammatory mediators suggests that chronic pulmonary infection in adults with CF may be a contributory factor in the long-term complications of low weight and bone disease.

Adult↗

PubMed2005

Influences of body composition upon the relative metabolic and cardiovascular demands of load-carriage.

AIM: To test the hypothesis that measures of aerobic fitness, body mass and indices of body composition will influence the metabolic and cardiovascular demands of simulated load-carriage tasks. METHOD: Twenty-eight healthy male volunteers, following assessment of maximal oxygen uptake (O(2)max) and body composition, walked on a treadmill at 4 kph (1.11 m/s) for 60 min on gradients of 0, 3, 6 and 9% whilst carrying backpack loads of 0, 20 and 40 kg. During the final 3 min of each 5-min exercise bout, indirect respiratory calorimetry and heart rate data were collected and the 'steady-state' metabolic O(2) and cardiovascular (heart rate) demands quantified. RESULTS: Absolute O(2)max (ml/min) produced the strongest correlation (r = -0.64, P < 0.01) with the metabolic demand of heavy load-carriage (40 kg). The body composition index lean body mass/(fat mass + external load) produced a moderate correlation (r = -0.52, P < 0.01) with the metabolic demand of heavy load-carriage. The increases in metabolic and cardiovascular demands were greater when the load carried increased from 20 to 40 kg compared with 0 to 20 kg at all four gradients. A model incorporating anthropometric and physiological characteristics with gradient and load explains 89% of the variability in the metabolic demands of load-carriage compared with 82% using gradient and load alone. CONCLUSION: The results show that indices of body composition as well as absolute aerobic power influence the relative metabolic demands of load-carriage. Application of these measurements would ensure selection criteria for load-carriage occupations are based on lean muscle mass rather than running speed.

Adult↗

PubMed2004

Age and sex variation in measures of body composition among the elderly Bengalee Hindus of Calcutta, India.

In the present cross-sectional study we examined 332 (171 men and 161 women) elderly (60 years and above) urban Bengalee Hindu resident in south Calcutta, India. Individuals were selected by random sampling procedure using local voter's registration list. Skin folds measures were used to compute body composition measures among them. There existed significant sex differences in various anthropometric body composition measures. Age had significant (p < 0.001) negative association with all anthropometric body composition measures namely percentage of body fat (PBF), fat mass (FM), arm muscle circumference (AMC), arm muscle area (AMA) and arm fat area (AFA) in both sexes. Fat free mass (FFM) in contrast had negative but not significant age impact. Regression analyses demonstrated that age had explained substantial amount of variance of PBF (men = 32%; women = 18.2%), FM (men = 18.2%; women = 12.8%), AMC (men = 23.4%; women = 19.2%), AMA (men = 22.2%; women = 10.2%) and AFA (men = 34%; women = 31%) in both sexes. Two-way ANOVA revealed age-sex interaction only had significant effect on FFM. The present investigation vindicated that there is a significant inverse age trends in anthropometric body composition measures among the Bengalee Hindus. Moreover, there existed sexual dimorphism in the effect of age on various anthropometric body composition measures.

Aged↗

PubMed1994

Comparative evaluation of body composition methods and predictions, and calculation of density and hydration fraction of fat-free mass, in obese women.

The objective of this study was to apply a three-component model of body composition to a group of obese women in order to (a) establish the relative value of a number of readily available prediction equations by comparison of the extent of agreement between these predictions and body composition estimated by the model and other reference methods and (b) evaluate density and hydration of fat-free mass. Estimation of body composition was carried out by reference methods and prediction equations and the usefulness of these prediction equations for application specifically to obese women was evaluated. The subjects were 15 obese, otherwise healthy, Caucasian women (body mass index > 30kg/m2 and body fat > 40% of body weight, as originally determined using densitometry). Body composition was estimated using three established reference methods (deuterium dilution which primarily measures total body water, densitometry for body fat and fat-free mass and total body potassium) and the three component model constructed from deuterium dilution and densitometry. Density and hydration fraction of the fat-free mass were calculated from appropriate values obtained as integral parts of the three-component model. In addition, body composition was predicted from various prediction equations incorporating weight and height (some of which include a factor for age), from a number of prediction equations utilizing different terms involving the same whole-body bio-electrical impedance measurement and from measurements of skinfold thickness and near infrared interactance. The extent of agreement between methods was assessed using bias and 95% limits of agreement. Mean density of fat-free mass was found to be 1.104 kg/l (s.d. 0.006kg/l) with a range of 1.093 to 1.117 kg/l, and mean hydration fraction was 0.712 (s.d. 0.016) with a range of hydration from 68.2% to 75.1% (all values were calculated from the three-component model). In general, the reference methods (densitometry, deuterium dilution, the three-component model and total body potassium) demonstrated better agreement with each other than with the prediction methods or equations. In these obese women, skinfold thickness measurements are apparently less reliable (large bias and 95% limits of agreement) than in the lean subjects of a variety of other studies. A majority of interpretations of weight and height measurements and predictions incorporating impedance/resistance measurements are apparently not applicable to this group of obese women, due to large values for both bias and 95% limits of agreement.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

PubMed1976

Simplified body-composition analysis using deuterium dilution and deuteron photodisintegration.

A number of approaches to estimating human body composition (water, lean mass, and fat) are available, and each approach has its own limitations. Deuterium dilution is a comparatively safe and valid procedure for assessing body composition; however, its use has been restricted by the relative complexity of measuring deuterium at low concentrations. A simplified scheme for quantifying low levels of deuterium in body fluid samples promises to expand the use of D2O in body composition studies. The deuterons are quantified by measuring the neutron emission induced by gamma-ray irradiation from 228Th(2.61 MeV). The in vitro aspects of the procedure exhibit coefficients of variation of under 1% throughout the range of assay and near 100% recovery of added D2O. In vivo comparison studies with a reference tritium dilution procedure indicate close agreement in a group of 38 subjects. The chief advantages of the procedure are a small oral dose of D2O and the use of either serum or urine samples. The physical condition of the sample does not affect the measurement so distillation is not required. Thus, small medical facilities can enjoy the advantages of low cost, minimum patient inconvenience, and technical simplicity by submitting subject samples to larger agencies for analysis.

Adipose Tissue↗

PubMed1992

Body composition and bone mass in post-menopausal women.

OBJECTIVE: We aimed to assess total body composition and to study the interrelationships between fat and lean tissue mass with total and regional bone mass in healthy British post-menopausal women. DESIGN AND PATIENTS: Total body composition and regional bone mass were measured in 97 healthy post-menopausal women recruited from the general community. The mean age was 57.9 years, range 49-65. MEASUREMENTS: Total body composition (fat, lean tissue and bone mineral) and regional bone density in the lumbar spine and femur were measured by dual energy X-ray absorptiometry on a Lunar DPX. RESULTS: Significant negative correlations with age were found for total body bone mineral density (r = -0.200, P = 0.049), and lumbar spine bone mineral density (r = -0.28, P = 0.006); the calculated rate of bone loss from these two sites was 0.33 and 0.7% per annum respectively. Fat tissue mass showed a positive correlation with age (r = 0.22, P = 0.03). High correlations were observed between total body and regional bone mineral density (r = 0.755-0.829, P < 0.001). After adjustment for age and lean mass, statistically significant correlations were seen between fat tissue mass and all bone mass measurements (P < 0.01-0.001), the strongest correlations being found for total body bone mineral content and density (r = 0.477 and 0.488 respectively). Lean tissue mass showed a strong correlation with total body bone mineral content (r = 0.580, P < 0.001), after adjustment for age and fat mass; it was less strongly correlated with other bone mass measurements than fat mass, showing only weak correlations with total body, trochanteric and lumbar spine bone mineral density (r = 0.228-0.246, P < 0.05). Age-adjusted body weight showed stronger correlations with total and regional bone mass than did either body mass index or height. CONCLUSIONS: Both fat and lean tissue mass are related to total and regional bone mass in post-menopausal women, the relationship being strongest for fat mass. Body weight shows stronger correlations with bone mass than either height or body mass index. In view of the direction and magnitude of changes in fat, lean tissue and bone mineral after the menopause, adiposity and muscularity are more likely to be determinants of peak bone mass than of the rate of post-menopausal bone loss.

Absorptiometry, Photon↗