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PubMed1984

Interrelation between body composition and endocrine system in healthy elderly people.

The body composition of 40 healthy aged and 20 healthy young people was determined using a multi-isotope method. At the same time their hormonal status was assessed. A correlation between the body composition and the endocrine status was investigated. Our results concerning the body composition and the hormonal values correlate with the findings of the literature. A strong correlation was found between the plasma volume and the renin-angiotensin-aldosterone system. The interrelation could explain the reciprocal age related changes of plasma volume and the renin-angiotensin-aldosterone system. No or weak correlation could be found between the body composition and other measured hormones.

Adult↗
PubMed1988

Total-body electrical conductivity method for estimating body composition: validation by direct carcass analysis of pigs.

Determination of body composition by measuring total-body electrical conductivity (TOBEC) is based on the principle that body fat and fat-free mass (FFM) differ in electrical properties. In humans, we are able to estimate body composition only by indirect methods, which have been used to validate the TOBEC instrument. Relationships between TOBEC and body composition were examined using direct carcass analysis of 24 pigs differing widely in body weight and composition (48-137 kg and 14-45% fat, respectively). Highly significant correlations (p less than 0.0001) were found between body conductivity and empty-body water (H2O) (r = 0.979), empty-body FFM (r = 0.980), empty-body crude protein (r = 0.962), and empty-body potassium (r = 0.949). Prediction of empty-body H2O or FFM from TOBEC had a SEE of 2.1 or 2.8 kg, respectively. Thus, the TOBEC method can predict body H2O and FFM over a wide range of body weight and fatness.

Adipose Tissue↗
PubMed1993

The use of bioelectrical impedance analysis for monitoring body composition changes during nutritional support.

Body composition was measured with bioelectric impedance analysis (BIA) in 30 patients with protein malnutrition following biliopancreatic diversion. Determinations were carried out prior to, during, and at the completion of intravenous nutritional support when the nutritional parameters had completely reverted to normal. Before treatment, body weight (BW), lean body mass (LBM), and body fat (BF) values were similar to those of controls, whereas the total body sodium/total body potassium (TBNa/TBK) and extracellular mass/body cell mass (ECM/BCM) ratios were considerably higher. During the support, no changes in BW, LBM, and BF were demonstrated, although a sharp decrease of TBNa/TBK and ECM/BCM was observed, thus demonstrating improved LBM composition. At the end of parenteral feeding, the BW, LBM, and BF values were similar to those observed before the support, while a further decrease in TBNa/TBK and ECM/BCM demonstrated a recovery towards normal of body composition. The full correspondence between clinical and BIA findings therefore suggests that this method may be valuable for monitoring body composition changes during nutritional support.

Adult↗
PubMed1996

Use of statistical methods to estimate body composition.

Epidemiologic investigations of chronic diseases in relation to body composition require large samples. This necessitates simple, reliable, and portable measures of body composition. Bioelectrical impedance analysis (BIA) variables and selected anthropometric characteristics are frequently used to predict body composition for groups or individuals when the application of sophisticated methods is not practical. We address statistical issues pertinent to the formulation of prediction equations for body composition from BIA measures and anthropometry, and factors associated with the accuracy and precision of the prediction equations.

Body Composition↗
PubMed2003

A follow-up study of the variations in the body composition of karate athletes.

We monitored body composition variations in nine elite karateists during a 3-year period (T(1), T(2), T(3)). Arm circumference (AC) and six skinfolds were measured. Arm muscle circumference (AMC) and area (AMA) were then calculated. Fat mass (FM) was calculated using the Durnin-Womersley, Sloan-Weir (S-W), Katch-McArdle and Lohman equations. The only significant increase regarded the AC, AMC and AMA measurements between T(1) and T(2). The time course of the predicted FM amount using the different equations was the same. In particular, the S-W equation did not seem to reflect the modifications in the amount of FM as evidenced by the total sum of the six skinfolds. Our subjects were characterized by a substantial uniformity in body composition parameters measured in this 3-year follow-up study.

Adult↗
PubMed1992

Skinfolds and body composition of sports participants.

Body composition of 1815 North-Italian young sports participants in relation to sex, age, sport and level of performance was investigated. About thickness and anatomical distribution of subcutaneous fat females showed skinfolds thicker than males. Significant differences were observed in skinfold thicknesses means of different sport-groups. Subscapular and forearm skinfolds were the best discriminant variables for males and females respectively. Body density was estimated according to Katch and McArdle (1973) and Durnin and Womersley (1974) equations. Males showed higher body density and lower fat percentage values than females. The lowest value of body density and the highest fat percentage were in male martial art competitors and in females practising skating and athletics. The highest values of body density and the lowest of fat percentage were in males practising athletics and rowing and in female martial art competitors. Highest and lowest values of fat-free mass were in games players and in soccer players and gymnasts respectively. "High aptitude" subjects showed higher fat-free mass values than "middle aptitude" group, besides a tendency towards higher body density values and lower fat percentage than "middle aptitude" group. With aging body density decreased whereas fat percentage and fat-free mass increased.

Adipose Tissue↗
PubMed1979

A review of body composition studies with emphasis on total body water and fat.

Tritiated water meausres a volume 4 to 15% body weight larger than that by desiccation, and, at present, only 0.5 to 2.0% of the overestimation can be explained by the exchange of hydrogen of tritiated water with those of the proteins and carbohydrates of the body. The remainder of the error is unexplained. Water in the lumen of the gut is an appreciable percentage of total body water (TBW) in many mammalian species, with the pig and the human as possible exceptions, and it should be considered an integral part of TBW. Consequently, the exclusion or inclusion of this transcellular water as part of TBW significantly affects the final TBW volume. As tritiated water exchanges with water in the gut, a comparison of the data from the indirect method with the data from the direct method can only be made when water in the gut is included in the desiccation method. Conceptually, the amount of water in lean body mass is a reflection of the actively metabolizing cell mass of the body. However, water in the gut is outside this cell mass, and if included, it significantly overestimates the water associated with the lean body mass compartment. The percentage of water in fat-free wet weight for most mature animals is estimated at 73.2%, although the mean values in the literature range from 63% for the beagle to 80% for the mouse, with the mean for the majority of species between 70 and 76%. If the percentage of water in fat-free wet weight lies between 70 and 76% for most species, then the error in calculating fat using the figure 73.2% in the equation (% fat = 100 - % TBW/0.732) is significant. In the application of this equation, the largest potential error lies in the estimation of TBW with tritiated water.

Adipose Tissue↗
PubMedDate not supplied

Effects of fluid retention on the measurement of body composition using bioelectric impedance.

Body composition measurements using bioelectrical impedance analysis (BIA) were performed on 50 uremic patients immediately before and after hemodialysis (HD) therapy, on 10 uremic patients under continuous ambulatory peritoneal dialysis (CAPD) therapy before and after the fluid was drained out of the peritoneal cavity and on 3 cirrhotic patients before and after abdominal paracentesis. Thirty-two pairs of measurements were performed on the CAPD patients and 3 pairs on the cirrhotic patients. Significant increases in both resistance and reactance were noted after HD. However, resistance and reactance before and after peritoneal fluid had been drained were not significantly different. In HD, body fluid loss as estimated by BIA (LBIA) was higher than that from the body weight method (LBW). The relationship between the two is described by the equation LBW = 0.841LBIA + 0.588. The total body fat estimated before HD was significantly lower than after HD, and it was significantly higher when measured with peritoneal fluid retention than with fluid drained. Generalized edema caused an increase in resistance and reactance, while local peritoneal fluid retention did not cause any significant changes. When total body fluid is measured by the BIA method, it is often overestimated in the case of generalized edema and underestimated in case of peritoneal fluid retention. Therefore, total body fat is underestimated by BIA in generalized edema before HD and overestimated in peritoneal fluid retention.

Adolescent↗
PubMed2002

Ageing, hormones, body composition, metabolic effects.

The age-associated, progressive changes in body composition are paralleled by a progressive decrease in hormone levels, among which there are testosterone (T) and growth hormone (GH). Moreover, the age-associated changes are rather similar to the changes in body composition seen in hypogonadism or hyposomatotropism, respectively. These age-associated changes in body composition are rather important: a decline in muscle mass by 20%-40% between the ages of 25 and 75, a doubling of fat mass and a decrease in bone mineral density by 0.3% per year after age 35. They have important functional and metabolic consequences. Most studies show a significant positive correlation between muscle mass and bone mineral density, respectively, and plasma T or GH levels, whereas abdominal fat mass is generally negatively correlated with T and GH levels. Whether, however, the hormone levels play a causal role or are the consequence of the changes in body composition is still an unsettled problem. The beneficial effects of hormone substitution on body composition suggest, nevertheless, that T and GH are at least co-determinants of the observed age-associated changes.

Aging↗
PubMed1992

Factors influencing body composition during very-low-calorie diets.

Apparent body composition changes with weight loss on very-low-calorie diet (VLCD) can depend on the method of fat-free mass estimation. In this report the implications of differences in measurement by direct versus indirect methods are examined. The nitrogen sparing and protein economy associated with ketosis is relevant and results of clinical trials with diets of varying composition are presented. The analytical findings of a multicenter, multimethod long-term VLCD study illustrate protein and metabolic conservation during VLCD. Protein losses, by total body nitrogen, over 10 wk dieting, independent of body mass index, were 4.75% of weight lost, as conservatively expected from obesity tissue reduction with no degradation of total energy expenditure. The implications of utilization of glycogen (water and potassium release) in interpretation of diet success and of body compositional change is evaluated. Evidence is presented that ultimate compositional changes with weight change may be individually specific and that body composition may be predicted from weight considerations alone.

Adipose Tissue↗
PubMed1998

Differential impact of conventional oral or transdermal hormone replacement therapy or tibolone on body composition in postmenopausal women.

OBJECTIVE: To compare the effects on body composition and body weight of tibolone vs two different sequential oral or transdermal oestrogen-progestogen hormone replacement therapies versus no therapy. PATIENTS AND METHODS: One hundred postmenopausal women were assigned to a control group (n = 26), or randomized to 1) tibolone (TIB) 2.5 mg/day (n = 28), 2) oral oestradiol 2 mg/day (PO) plus sequential dydrogesterone 10 mg/day for 14 of 28 days per cycle (n = 26), or 3) transdermal oestradiol patch (TTS) releasing 50 micrograms/day plus oral sequential dydrogesterone 10 mg/day for 14 of 28 days per cycle (n = 20). Body composition was measured at the base-line and every 6 months for 2 years by DXA (Hologic QDR 1000 W). RESULTS: Total body fat mass increased (P < 0.05) in controls (+3.6 +/- 1.5%) and in TTS treated (+4.7 +/- 2.2%), but not in PO (-1.2 +/- 2.4%) and TIB (-1.6 +/- 2.2%) treated subjects. This increase in total fat mass in controls and TTS treated women was mostly due to an increase in fat mass of the trunk (P < 0.05), but not legs. As a result, a redistribution of body fat to the trunk occurred in controls, TTS and TIB, but not in PO treated women (P < 0.05). Total lean body mass decreased (P < 0.02) in controls (-1.7 +/- 0.7%) and PO (-1.4 +/- 0.6%) but not in TTS (+0.3 +/- 0.8%) and TIB (+0.4 +/- 0.5%) treated subjects. CONCLUSIONS: The menopause is associated with an increase in total body fat and a decline in lean body mass. Oral oestradiol/dydrogesterone and tibolone prevent total body fat changes, whereas transdermal oestradiol/oral dydrogesterone and tibolone prevent the lean mass changes. Furthermore, oral oestradiol/dydrogesterone prevents the shift to a central, android fat distribution.

Absorptiometry, Photon↗
PubMed2001

The prediction of body composition in Chinese Australian females.

OBJECTIVE: To determine the efficacy of applying specific body composition techniques to, and assess the relationship between body mass index (BMI) and body fat levels for Chinese Australian females. DESIGN: Statistical comparative analysis of body composition techniques. SUBJECTS: Australian resident females of Chinese extraction (n=40) (aged 18-45 y, mean 32.5+/-8.0; BMI range 15.7-30.9 kg/m2, mean 21.7+/-3.1 kg/m2, median 20.8 kg/m2). MEASUREMENTS: Body composition determined using bio-electrical impedance analysis (BIA), the skin-fold equations of Durnin and Womersley (D&W) and a deuterium dilution technique. Body size was calculated as the body mass index (BMI) weight/height(2) (kg/m2). RESULTS: With a median BMI of 20.8, range 15.7-30.9, an acceptable BMI existed for 87.5% of the subjects (mean (s.d.) 21.7+/-3.1 kg/m2). Percentage fat mass (%FM) from the deuterium dilution technique (mean (s.d.) 35.6+/-6.4) suggested 75% were overweight or obese. %FM from the D&W equation (mean (s.d.) 28.0+/-3.9) and BIA (mean (s.d.) 29.4+/-5.1) also indicated a tendency towards overweight or obese. The deuterium technique was significantly correlated and significantly different to the D&W eqn, r=0.71 P=0.001; and BIA, r=0.77, P=0.001. Bland and Altman analysis indicated that bias existed between the techniques (BIA mean (s.d.)-6.7+/-4.1) and D&W equation mean (s.d.)-6+/-4.5) when compared to the deuterium method. CONCLUSIONS: Despite a low mean BMI, body fat levels determined by the three methods suggested that, overall, an unsatisfactory body composition existed. The levels of overweight and obesity (%FM>30) were higher than reported in previous research despite a mean BMI lower than the Australian national average. Comparative analysis suggested that the body fat prediction techniques used may be precise but not accurate. Comparative results obtained for the BIA and D&W equation techniques suggest an overestimation of body fat levels for leaner individuals and under estimation for overfat individuals. The results support the notion that accurate determination of body composition and the determination of appropriate body size may require equations developed for specific ethnic populations.

Adolescent↗
PubMed1980

Body composition of synchronized swimmers.

The body composition of 15 synchronized swimmers and 15 non-athletic female controls were compared. Body fat and lean body weight were calculated from body density measurements. Swimmers were ranked according to skill level and ability in an attempt to predict success in synchronized swimming from percent body fat or lean body weight. A student t-test revealed no statistically significant differences between groups for height, weight, percent body fat or lean body weight. Non-significant rank order correlations between ability ranking and percent fat (r = -.31) and lean body weight (r = -.18) point to the inability to predict success in synchronized swimming from these variables. These data were compared with female athletes of other sports.

Adult↗
PubMed1998

Validation of predictive equations for use of deuterium oxide dilution to determine body composition of dogs.

OBJECTIVE: To validate equations predicting body composition of dogs, using deuterium oxide dilution. ANIMALS: 38 female and 37 male dogs selected by defined body weight and body condition criteria. PROCEDURE: Measured equilibrated deuterium concentration in serum after i.v. administration of isotope was used to determine isotope space and predict body water, fat, nitrogen, and ash contents determined from analysis of homogenized carcass. Equations predicting body composition were derived, using regression analysis, and were validated, using data-splitting techniques. RESULTS: Deuterium space (in kilograms) overestimated kilograms of body water content by mean 21.8% +/- SD of 4.18%. Regression equations were derived and validated to predict kilograms of body water and ash from kilograms of deuterium space, and proportion of body water, fat, nitrogen, and ash from proportion of deuterium space. Coefficients of determination (r2) and means of standard errors of estimating new values (SEE) were, respectively, 0.993 and 0.4 kg for body water content, and 0.942 and 0.08 kg for ash content. For proportions, SEE were 2.0, 2.7, 0.1, and 0.4% for body water, fat, nitrogen, and ash, respectively. Two factors, time for isotope equilibration and whether samples were processed by vacuum sublimation, improved SEE for proportion of body water from 2.0 to 1.3% and of fat from 2.7 to 1.8%. Equations predicting absolute quantities of fat and nitrogen could be derived but not validated. CONCLUSIONS: Deuterium dilution can be used to predict body composition of dogs with precision equal to that determined for other species.

Animals↗
PubMed1995

An evaluation of the use of total body electrical conductivity for the estimation of body composition in adult rats: effect of dietary obesity and adrenalectomy.

Total body electrical conductance (TOBEC) has been recommended for serial measurements of body composition in animals and humans. This study examined the accuracy of the TOBEC technique in predicting body composition of a population of adult male rats that had undergone seven different treatments, including adrenalectomy and blocking of glucocorticoid receptors, in the study of the etiology of obesity. The predicted body composition values of the animals (n = 57, body weight 550 +/- 8 g) obtained by using the manufacturer's and Baer's equations were compared to the actual body composition obtained by direct carcass analysis. Both equations underestimated lean body mass and reciprocally overestimated body fat (manufacturer's 103 +/- 4 g, Baer's 55 +/- 3 g). A new prediction equation was developed based on the conductivity index and the actual lean body mass. This revised equation was able to accurately estimate the lean body mass of the animals used in the same experiment but over-estimated lean body mass of larger animals (n = 10, wt. 647 +/- 13 g). Conclusions based on multiple comparisons (Duncan's) of predicted and actual values resulted in different effects of treatments on body composition. To improve accuracy and reliability of the TOBEC technique, a prediction equation should be developed from the same population as the studied population, and experimental group sizes used for examining treatment effects should be relatively large.

Adipose Tissue↗
PubMed1984

Nutritional thriftiness and human reproduction: beyond the critical body composition hypothesis.

The 'critical body composition hypothesis' (CBCH) is frequently used to explain variations in the duration of postpartum amenorrhea. The hypothesis predicts that ovulation will not occur it fat reserves fall below a critical threshold. This paper attempts to analytically separate the CBCH from the broader concept of nutritional thriftiness on which it is based. A review of previous research on fat cell metabolism and ovulation finds no direct link between fatness and fecundity. Rather they are each regulated by the lactation and mother-infant interactions associated with breast feeding. As a system which delivers available fat into breast milk and prevents ovulation only during the time when the infant is dependent on the mother, the pathways outlined here represent a nutritionally thrifty method of fertility regulation, one which maximizes reproductive success while minimizing energy investment. The cultural patterning both of infant feeding behaviors and the wider range of maternal activities which affect breast feeding suggest specific testable hypotheses to explain interpopulation variations in fertility and infant nutritional status.

Adipose Tissue↗